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THE 

SUBWAYS  AND  TUNNELS 

OF  NEW  YORK 
METHODS    AND    COSTS 


WITH    AN    APPENDIX    ON     TUNNELING    MACHINERY    AND 
METHODS   AND    TABLES  OF  ENGINEERING    DATA 


BY 

GILBERT  H.    GILBERT,   LUCIUS  I.    WKiHTMAN 

AND 

W.    L.   SAUNDERS 


FIRST    EDITION 
FIRST    THOUSAND 


NEW    YORK 

JOHN   WILEY  &    SONS 

London:    CHAPMAN  &  HALL,   Limited 
1912 


Copyright,  1912, 

BY 

GILBERT  H.  GILBERT,  LUCIUS  L  WIGHTMAN 

AND 

W.  L.  SAUNDERS 


THE    SCIENTIFIC    PRESS 

ROBERT    DRUMMOND     AND    COMPANY 

BROOKLYN,     N.    Y. 


Engineering 
Library 

Tf 

K7^3 


TRIBUTE 


No  record  of  tunneling  under  the  rivers  surrounding  New 
York  is  complete  without  a  tribute  of  admiration  and  respect 
to  the  genius  and  ability  shown  by  the  men  who  were  the 
architects  and  builders.  It  has  for  a  long  time  been  an  easy 
matter  to  tunnel  through  rock.  The  power  drill  simply  added 
to  the  efficiency  of  rock  tunneling  and  in  doing  this  it  was  made 
possible  to  build  great  tunnels  for  railways,  aqueducts,  etc., 
within  a  reasonable  time  and  at  reasonable  expense. 

To  build  and  maintain  tunnels  through  silt  or  other  alluvial 
material,  especially  tunnels  of  large  diameter,  was  a  problem 
which  had  not  been  solved  by  engineers  as  late  as  1874.  At 
that  time  Mr.  Delos  E.  Haskin  came  to  New  York  from  San 
Francisco,  where  he  had  made  a  fortune,  every  dollar  of  which 
he  lost  in  an  effort  to  prove  the  practicabiHty  of  tunneling  under 
the  Hudson  River  and  through  the  silt  by  means  of  compressed 
air.  Though  Haskin  did  not  live  to  enjoy  the  fruits  of  his  work, 
he  proved  the  practicabiHty  of  his  scheme  in  a  general  way  and 
to  him  belongs  the  credit  as  the  genius  who  pushed  the  idea  to  the 
front. 

Next  came  Mr.  Charles  M.  Jacobs,  who  combined  the  genius 
and  enthusiasm  of  Haskin  with  the  ability  of  the  engineer.  Mr. 
Jacobs  built  the  first  tunnel  under  the  rivers  about  New  York, 
namely,  the  East  River  Gas  Tunnel  from  New  York  to  Brooklyn. 
After  this  he  took  up  with  enthusiasm  the  completion  of  the  old 
Haskin  tunnels,  maintaining  with  earnest  zeal  the  practicability 
of  the  scheme,  modified  on  lines  of  his  own  experience,  until 
he  succeeded  in  completing  these  and  the  Pennsylvania  tunnels, 
which  are  described  in  this  volume.     In  the  darkest  days  of 


VI  TRIBUTE 

tunneling  under  these  rivers  Mr.  Jacobs  never  lost  courage. 
When  the  work  began  he  was  on  the  job  at  all  times,  and  his 
genius  and  engineering  capacity  are  shown  throughout  this 
great  work.  He  has  now  returned  to  his  home  in  England, 
and  well  does  he  deserve  the  reputation  and  wealth  which  he 
has  achieved. 

Mr.  WilHam  G.  McAdoo,  with  great  foresight  and  abiHty, 
planned  and  executed  that  gateway  to  New  York,  through 
tunnels  under  the  Hudson,  which  is  called  the  McAdoo  System. 
Of  these  three  men  Haskin  was  the  enthusiast,  Jacobs  the  engi- 
neer and  McAdoo  the  business  man. 

W.  L.  Saunders. 


PREFACE 


The  system  of  subways  and  tunnels  in  and  about  New  York 
City  is  the  result  of  traffic  conditions  which  are  entirely  without 
parallel  in  any  other  city  of  the  world.  The  island  of  Man- 
hattan, comprising  the  Borou  h  of  Manhattan  of  the  City  of 
New  York,  is  a  little  less  than  twelve  miles  in  length  and,  at 
the  widest  point,  a  trifle  over  two  miles  in  width;  yet  it  is  the 
business  center  of  a  population  aggregating  probably  close  to 
six  minions.  The  census  of  1910  credits  New  York  City  with  a 
population  of  something  over  four  milhons.  But  when  to  this 
figure  are  added  the  inhabitants  of  the  adjacent  cities  in  New 
Jersey,  New  York  and  Connecticut  which  are  within  commuting 
distance,  six  millions  is  probably  a  fair  estimate  of  the  popula- 
tion, the  business  pivot  of  which  is  found  in  the  island  of  Man- 
hattan. The  actual  business  center  for  this  vast  number  may 
be  further  restricted  to  a  section  south  of  426.  Street,  the  upper 
part  of  the  island  being  principally  residential  in  character. 

A  consideration  of  these  figures  will  reveal  the  magnitude 
and  complexity  of  the  traffic  problem  in  New  York  City. 
The  East  River  intervenes  between  Manhattan  and  the 
Boroughs  of  Brooklyn  and  Queens,  and  the  suburban  towns 
of  Long  Island  New  York  Bay  separates  the  Borough  of 
Richmond  (Staten  Island).  The  Hudson  River  divides  the 
industrial  and  suburban  territories  of  New  Jersey  from  New 
York.  On  the  north,  the  Harlem  River  divides  the  Borough 
of  the  Bronx,  and  the  towns  of  New  York  State  and  Connecticut, 
from  their  business  center. 

Every  business  day  in  the  year  a  vast  tide  of  humanity 
converges  on  the  business  center  of  New  York  City.     Through- 


viii  PREFACE 

out  the  business  day  a  large  percentage  of  these  business  men 
and  women,  and  shoppers,  must  be  furnished  quick  and  safe 
transportation  within  the  Hmits  of  the  island.  Every  evening 
this  tide  diverges  to  its  homes.  This  morning  and  evening 
migration  must  all  be  accomphshed  within  the  space  of  an  hour 
or  so.  The  magnitude  of  the  transportation  problem  here 
presented  has  called  for  the  greatest  engineering  genius  and 
almost  unlimited  capital;  and  its  solution — by  no  means  com- 
plete as  yet — finds  its  beginning  in  the  transit  system  of  which 
the  New  York  subway,  and  the  North  and  East  River  tunnels 
with  their  connections,  are  a  part. 

The  ferry  systems  from  New  Jersey,  Long  Island  and  Staten 
Island  have  reached  the  limit  of  their  capacity.  The  East 
River  bridges  furnish  relief  to  the  situation,  but  are  by  no  means 
sufficient.  The  elevated  and  surface  car  systems  of  New  York 
and  Brooklyn  have  been  extended  to  their  practical  limit. 
With  surface,  above-surface,  and  over-water  means  of  transit 
incapable  of  further  expansion,  the  only  alternative  was  to  make 
use  of  the  subterranean  and  subaqueous  territory  underlying 
and  adjacent  to  the  greater  city.  The  subways,  and  sub- 
aqueous and  land  tunnels,  in  and  about  New  York  City  may  be 
considered  as  simply  a  beginning  of  a  vast  system  of  sub-surface 
transportation  which  must  develop  with  the  growth  of  population. 

The  present  Interboro  Rapid  Transit  Subway  consists  of  a 
trunk  line  starting  in  Brooklyn,  passing  under  the  East  River, 
entering  Manhattan  at  the  Battery,  and  following  the  back- 
bone of  the  island  to  its  northern  extremity,  with  a  branch  to 
the  Bronx  passing  under  the  Harlem  River. 

The  Pennsylvania  Railroad  and  Long  Island  Railroad  sys- 
tem comprises  a  series  of  surface,  subaqueous  and  subterranean 
lines  starting  at  Harrison,  N.  J.,  crossing  the  meadows  on  the 
surface,  penetrating  Bergen  Hill  by  tunnel,  plunging  beneath 
the  Hudson,  or  North  River,  through  two  subaqueous  tunnels, 
traversing  Manhattan  through  the  crosstown  tunnels,  passing 
beneath  the  East  River  through  four  subaqueous  tunnels,  and 
emerging  on  the  surface  at  Long  Island  City.  This  system 
may  be  said  to  properly  include  the  great  Pennsylvania  Passen- 


PREFACE  ix 

ger  Terminal  in  New  York  City,  with  its  sub-surface  yards. 
Its  object  is  not  only  to  give  quick  access  to  the  heart  of  Man- 
hattan for  the  commuting  service  of  Long  Island  and  portions 
of  New  Jersey,  but  to  provide  also  a  city  terminal  for  the  Penn- 
sylvania through  traffic  from  the  West. 

The  so-called  McAdoo  System  is  for  suburban  service 
entirely.  It  includes:  A  sub-surface  belt  line,  or  tunnel,  along 
the  Jersey  shore  connecting  three  railroad  terminals;  four 
subaqueous  tunnels  under  the  Hudson;  and  a  line  of  subway 
from  the  terminus  of  two  of  its  Hudson  River  tunnels  northward 
under  Manhattan  Island. 

Under  the  East  River  are  the  Belmont  tunnels,  completed 
but  not  yet  in  operation,  from  Long  Island  to  Manhattan. 
They  will,  probably,  later  be  made  a  part  of  the  great  traffic 
arteries  of  New  York. 

The  tunnel  and  subway  system  serving  the  population 
centering  in  New  York  thus  includes:  One  complete  subway 
system  connecting  three  boroughs;  eight  subaqueous  tunnels 
under  the  East  River;  six  subaqueous  tunnels  under  the  Hud- 
son River  to  the  mainland;  two  subaqueous  tunnels  under  the 
Harlem  River  to  the  Bronx;  the  belt-Hne  tunnels  and  the 
New  York  subway  of  the  McAdoo  System;  and  the  Bergen 
Hill  and  crosstown  tunnels  of  the  Pennsylvania  Railroad. 

In  the  aggregate  these  enterprises  probably  involve  as  much 
capital  as  the  building  of  the  Panama  Canal — and  possibly 
even  more.  They  have  encountered  at  every  stage  obstacles 
stupendous  in  magnitude  and  difficulty,  and  calling  for  engineer- 
ing methods  beyond  all  precedent.  They  represent  engineering 
and  contract  achievement  of  such  vast  importance  that  they 
mark  a  new  era  in  construction  work. 

The  authors  here  acknowledge  their  indebtedness  to  the 
many  engineers  and  contractors  whose  records  and  papers  have 
furnished  so  much  of  the  information  in  these  pages.  Individual 
credit  has  been  given  in  many  places  throughout  the  book. 
But  in  many  cases  the  authority  is  not  stated,  simply  because 
the  data  given  is  a  compilation  from  a  number  of  sources. 
Acknowledgment  is  also  made  to  the  Ingersoll-Rand  Company 


X  PREFACE 

and  to  the  Cameron  Steam  Pump  Works  for  photographs  and 
tables  of  engineering  information;  to  the  American  Society  of 
Civil  Engineers  for  the  use  of  many  valuable  plates  and  illus- 
trations; a.nd  to  Compressed  Air  Magazine,  horn  which  several 
important  papers,  with  their  illustrations,  have  been  taken. 

The  Authors. 


CONTENTS 


PAGE 

Tribute v 


Preface 


vu 


CHAPTER  I 

Topography,  Geological  Formation  and  Historical  Data i 

CHAPTER  II 
The  Original  Hudson  Tunnel 7 

CHAPTER  III 
The  East  River  Gas  Tunnel lo 

CHAPTER  IV 

]\Ianhattan-Bronx  Division  of  the  New  York  Subway i6 

CHAPTER  V 

The  Brooklyn-Manhattan  Division  of  the  New  York  Subway.  .     27 

CHAPTER   \'l 

Compressed  Air  in  the  Subway  Construction;    Costs  of  Exca- 
vation IN  THE  New  York  Subway 32 

CHAPTER  \  II 

The  Pennsylvania  Railroad  Developments  in  and  near  New 
York  City 37 

xi 


xii  CONTENTS 


CHAPTER  VIII 

PAGE 

Bergen  Hill  Tunnels  of  the  Pennsylvanl\  Railroad 46 


CHAPTER  IX 

North  River  Tunnels  of  the  Pennsylvania  Railroad 57 

CHAPTER  X 

North  River  Tunnels  of  the  Pennsylvania  Railroad — (Continued)    68 

CHAPTER  XI 
North  River  Tunnels  of  the  Pennsylvania  Railroad — (Continued)     77 

CHAPTER  XII 

Excavation  for  the  Terminal  Station  of  the  Pennsylvania 
Railroad 91 

CHAPTER  XIII 
Cross-town  Tunnels  of  the  Pennsylvania  Railroad 104 

CHAPTER  XIV 
The  East  River  Tunnels  of  the  Pennsylvania  Railroad iii 

CHAPTER  XV 

The  East  River  Tunnels  of  the  Pennsylvania  Railroad — (Cant.).  123 

CHAPTER  XVI 
The  East  River  Tunnels  of  the  Pennsylvania  Railroad — (Cont.).  133 

CHAPTER  XVII 
The  East  River  Tunnels  of  the  Pennsylvania  Railroad — (Cont.).  143 

CHAPTER  XVIII 
The  Belmont  Tunnels 148 


CONTENTS  Xlil 

CHAPTER  XIX 

PAGE 

The  Hudson-Manhattan  Tunnels 145 

CHAPTER  XX 
The  Hudson-Manhattan  Tunnels — {Continued) 150 

1      CHAPTER  XXI 

The    Hudson    Terminal    Station    of    the    Hudson-Manhattan 
Tunnels 158 


APPENDICES 

APPENDIX  A 

Air  Compressors  in  the  New  York  Tunnel  Work 185 

APPENDIX  B 
The  Compressed  Air  Plenum 205 

APPENDIX   C 
The  Use  of  Compressed  Air  in  Tunneling 210 

APPENDIX  D 
Special  Types  of  Air  Compressors 217 

APPENDIX  E 
Straight  Line  and  Duplex  Compound  Alr  Compressors 226 

APPENDIX  F 

Compound  Air  Compression;  Altitude  Compression;  Air  Cylin- 
der Lubrication 237 


XIV  CONTENTS 

APPENDIX   G 

PAGE 

Some  Air-lift  Data  .    . , 251 

APPENDIX  H 
CoiTPRESSED  Air  Locomotives 256 

APPENDIX  I 

Rock  Drills;  Hammer  Drills 262 

APPENDIX  J 
Tunnel  Carriage  for  Drilling;   Electric- Air  Drill 281 

APPENDIX  K 

Rock-Drill  Bits;  Drill  Sharpening 295 

APPENDIX  L 

Explosives;     Dampness    and    Dynamite;     Blasting    Gelatine; 
Cost  of  Blasting  in  Open  Cuts 307 

APPENDIX   M 
Pumps  for  Sinking  and  Tunneling;  Sinking  Caissons 319 

APPENDIX  N 
Engineering  Data 34c 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


CHAPTER  I 

TOPOGRAPHY,  GEOLOGICAL  FORMATION  AND   HISTORICAL  DATA 

The  island  of  Manhattan  is  a  rocky  ridge  lying  north  and 
south  and  having  an  area  of  approximately  14,000  acres  or  22 
square  miles.  It  is  in  the  upper  end  of  New  York  Bay,  between 
the  Hudson  River  on  the  west  and  the  East  River  on  the  east, 
with  the  Harlem  River  and  Spuyten  Duyvil  Creek,  small  con- 
necting tideways,  separating  it  from  the  mainland  on  the  north 
and  northeast. 

Manhattan  Island,  as  well  as  the  adjacent  country  to  the 
north  and  east,  is  principally  a  formation  of  rock  composed 
chiefly  of  gneiss  and  mica  schist,  with  heavy  seams  of  coarse- 
grained dolomitic  marble  and  thinner  layers  of  serpentine  run- 
ning through  it.  These  rocks  are  supposed  to  be  Lower  Silurian 
in  character.  Rocks  of  the  Lower  Silurian  era  are  mainly 
sandstone,  shales,  conglomerates  and  Umestones;  but  Pro- 
fessor Newberry  holds  that  they  have  so  great  a  similarity  to 
some  portions  of  the  Laurentian  Range  in  Canada,  that  it  is 
difficult  to  evade  the  conviction  that  they  are  of  the  same  period. 

The  deep  troughs,  through  which  the  Hudson  and  East 
Rivers  find  their  way  through  New  York  harbor  to  the  ocean, 
are  supposed  by  the  same  authority  to  have  been  excavated 
during  the  late  Tertiary  period  when  Manhattan  Island  and 
the  other  islands  in  New  York  Bay  stood  much  higher  than  they 
do  now,  when  Long  Island  did  not  exist,  and  when  a  great  sand 
plain  extended  beyond  the  Jersey  coast  some  eighty  miles 
seaward. 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


SECTION  N  O 

about  200th  St. 


SECTION    L  M 

about  WJth  St 


SECTION    I  K 
about  liOth  St . 


SECTION   G  H 
about  95th  St. 


SECTION  A  B 
ab — t  I'aik  Place 


Sand-Made  Ground 
Clay-River  Mud 

Claj 

Clay 

Gravel  125"  fu  doini 

QueiBa 


Drift 
GoeiaB 


Cross-sections    of    Manhattan   Island, 
showing  Geological  Formations. 


For  half  its  length  north- 
ward from  its  lower  point, 
Manhattan  Island  slopes  on 
either  side  from  a  central 
ridge.  On  the  upper  half  of 
the  island  the  ground  rises 
precipitously  from  the  Hud- 
son River  in  a  narrow  line  of 
hill  which  on  the  eastern  side 
sinks  rapidly  to  a  plain  known 
as  the  Harlem  Flats,  border- 
ing on  the  Harlem  and  East 
Rivers.  The  surface  through- 
out the  island  is  rocky,  with 
the  exception  of  this  plain. 

The  district  beyond  the 
Harlem  River,  as  far  north  as 
Yonkers,  is  traversed  by  lines 
of  rocky  hills  trending  north 
and  south.  Some  idea  of  the 
varied  outline  which  was  once 
characteristic  of  the  whole 
island  can  be  gathered  from 
the  present  surface  formation 
of  Central  Park.  The  bed  of 
the  Hudson  River  is  a  deposit 
resulting  from  the  washing 
away  of  the  rocks  of  the  upper 
river  in  the  form  of  silt,  shale, 
sandstone  or  other  sedimen- 
tary or  metamorphic  rock, 
and  a  trap  rock  of  the  Pali- 
sades formation. 

Note.  From  Dana's  Geology; 
Newberry's  Geological  History  of  New 
York  Island;  Edwin  L.  Godkin,  En- 
cyclopedia Britannica;  Report  of  the 
Chamber  of  Commerce  of  the  State  of 
New  York,  1905. 


TOPOGRAPHY,  GEOLOGICAL  FORMATION,  ETC. 


TJnder 


Long-  Island  City 


Weeha 


,y^„  ^    \  "Williamsburg 


Xavy  Yard 


Jersey 


Approximate  Line  of  The  Tuuucl^— 

Geological  Map  of  Manhattan  Island,  with  Route  of  the  Original  Rapid 

Transit  Subway. 


4       SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

From  the  first  settlement  of  Manhattan  Island  by  the  Dutch, 
two  or  three  years  after  Hudson's  visit  in  1609,  until  1700,  the 
population  had  become  about  21,700  In  1800  this  had  grown 
to  60,500;  in  1820  to  124,000.  From  that  time  the  population 
has  increased  until  it  has  successively  covered  the  district  south 
of  Wall  Street,  south  of  Canal  Street,  south  of  23d  Street,  south 
of  42d  Street,  south  of  the  Harlem  River;  and  it  now  extends 
north  of  the  Harlem  along  the  Hudson  River  well  toward  Yon- 
kers,  and  on  the  east  toward  Long  Island  Sound. 

The  population  of  the  municipality  is,  as  already  stated, 
approximately  four  millions. 

The  first  settlement  was  at  the  extreme  southern  end  of  the 
island  The  commerce  of  that  day  was  gathered  at  this  point, 
and  this  section  remains  to-day  the  great  center  of  finance, 
trade  and  commerce.  The  metropolitan  center,  including  the 
nearby  cities  of  New  Jersey,  New  York  and  Connecticut, 
embraces  a  total  population  of  probably  six  millions  and  is, 
with  the  exception  of  London,  the  largest  center  of  population 
in  the  world.  The  growth  from  south  to  north,  covering  an 
extent  of  more  than  ten  miles,  has  been  restricted  on  the  eastern 
and  western  sides  by  the  East  and  Hudson  Rivers.  The  con- 
ditions of  growth  and  population  have  demanded  rapid  and 
certain  means  of  travel  between  the  different  sections  and  the 
general  center. 

At  the  beginning  of  the  last  century  small  stages  met  all 
transit  requirements.  With  the  advent  of  steam  ferries,  about 
1820,  transportation  across  the  rivers  was  facilitated.  In  1850 
stage  and  omnibus  lines  served  the  population  and  were  a  little 
later  superseded  by  tram  cars. 

Rapid  transit  in  a  sense  somewhat  approaching  the  present 
understanding  of  the  term  was  introduced  in  1875,  when  trains 
were  brought  into  the  Grand  Central  Station  at  4 2d  Street 
over  a  four-track  system.  A  short  section  of  elevated  railroad 
had  been  erected  in  Greenwich  Street  in  1870.  Ten  years  later 
elevated  railway  structures  had  been  completed  to  the  Harlem 
River.  The  opening  of  the  Brooklyn  Bridge  in  1883,  and  the 
further  extension  of  the  system  of  elevated  roads,  brought  the 


TOPOGRAPHY,  GEOLOGICAL  FORMATION,  ETC.     5 

outlying  districts  within  reasonable  traveling  time  of  New  York 
City.  In  1884  the  cable  system  of  propelling  street  cars  was 
introduced,  to  be  later  displaced  by  electric  railway  systems. 

From  1868  to  1900  many  projects  and  schemes  were  put 
forth  to  improve  transit  facihties  Among  the  first  was  the 
Beach  Pneumatic,  incorporated  in  1868,  and  known  as  the 
Broadway  Underground  Railway.  It  was  the  only  one  upon 
which  constructive  work  was  actually  done.  The  charter  of 
this  company  provided  that,  to  demonstrate  the  practicability 
of  its  plans  "  to  transmit  letters,  packages  and  merchandise, 
etc.,  it  must  first  lay  down  and  construct  one  line  of  said 
pneumatic  tubes,  etc."  A  full-sized  section  of  the  tunnel  was 
built  on  the  lines  adopted  and  is  to-day  in  good  condition. 
In  1873  this  company's  charter  was  amended  to  permit  it  to 
construct,  maintain  and  operate  an  underground  railway  for 
the  transportation  of  passengers  and  property.  It  was  pro- 
posed to  operate  the  tunnel  by  means  of  compressed  air,  a  car 
circular  in  cross-section  being  used,  approximately  fitting  the 
interior  of  the  tube.  It  was  pointed  out  that  by  this  means 
the  obnoxious  gases  from  the  combustion  of  coal  in  locomo-, 
tives  would  be  done  away  with. 

Work  w^as  begun  on  the  tunnel  at  the  corner  of  Broadway 
and  Warren  Street,  and  a  section  was  built  under  Broadway 
to  the  southern  side  of  Murray  Street.  The  straight  portions 
of  the  tunnel  were  lined  with  brick  to  a  diameter  of  eight  feet 
in  the  clear;  the  curved  portions  were  of  cast  iron.  The 
tunnel  was  built  by  means  of  a  shield,  which  was  forced  forward 
two  feet  at  a  time  by  hydrauhc  jacks. 

Early  in  1870  the  tunnel  was  open  for  inspection.  A  car 
was  run  from  one  end  to  the  other  with  the  object  of  demon- 
strating the  safety  and  practicability  of  the  plan.  The  work 
done  failed  of  successful  issue.  Engineers  were  divided  in 
opinion  as  to  the  possibility  of  building  an  underground  tunnel 
under  narrow  streets  in  front  of  such  massive  structures  as 
the  Astor  House.  Owing  to  this  difference  of  opinion  on  the 
part  of  the  experts  financial  support  could  not  be  obtained 
and  the  project  was  dropped. 


6       SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

In  187 1  the  Gilbert  Elevated  Railroad  was  chartered  for 
the  purpose  of  constructing  a  pneumatic  tube  railway.  It  was 
proposed  to  erect  a  pneumatic  tube,  supported  from  arches 
above  the  street.  It  was  claimed  that  the  road  would  be 
noiseless  and  the  train  out  of  sight.  This  plan  was  found 
impracticable  and  too  expensive,  and  it  was  decided  to  build 
the  tube  without  a  top,  and  to  operate  a  steam  road  in  the 
trough  thus  formed.  Finally  the  trough  also  was  abandoned 
and  the  plan  resolved  itself  into  a  simple  elevated  railroad, 
the  outgrowth  of  which  are  the  present  elevated  railway  systems 
of  the  city. 


CHAPTER   II 

THE   ORIGINAL   HUDSON  TUNNEL 

In  187 1  D.  C.  Haskins  conceived  the  idea  of  building  a 
tunnel  under  the  Hudson  River.  In  making  a  trip  from  the 
Pacific  Coast  via  Omaha  he  had  been  struck  with  the  system 
of  building  piers  for  a  railway  bridge  over  the  Missouri  River. 
This  system  was  the  forming  of  caissons  made  up  of  a  number 
of  iron  rings  bolted  together  and  constituting  a  cylinder  which 
could  be  lengthened  by  the  addition  of  rings  as  the  caisson 
descended.  Air  locks  and  compressed  air  were  used,  the  material 
within  the  caisson  being  excavated  by  hand  till  a  bed  rock 
foundation  was  reached. 

From  a  study  of  this  work  Mr.  Haskins  conceived  the  idea 
that  iron  cylinders  fitted  with  air  locks  could  be  placed  horizon- 
tally, and  tubular  tunnels  under  the  Hudson  River  could  be 
started  from  the  bottom  of  a  shaft  by  using  compressed  air 
to  prevent  the  inflow  of  earth  and  water.  As  the  material 
was  excavated  in  front  of  the  tunnel  the  latter  was  to  be 
advanced  by  the  addition  of  rings  of  the  diameter  of  the  finished 
tube.  Work  on  such  a  tunnel  under  the  Hudson  River  to  con- 
nect New  Jersey  and  New  York  was  commenced  on  the  New 
Jersey  side  in  November,  1874.  The  bed  of  the  Hudson  is  a 
silt  deposit,  which  when  dry  is  an  impalpable  powder,  but  when 
saturated  with  water  is  as  fluid  as  quicksand.  When  a  certain 
degree  of  moisture  is  carried  by  this  material  it  has  a  con- 
sistency approximating  that  of  clay.  This  latter  character- 
istic was  taken  advantage  of  by  maintaining  an  air  pressure 
in  the  heading  equal  to  the  hydrostatic  head  outside,  when  the 
material  to  be  excavated  formed  a  barrier  against  the  entrance 
of  water,  thus  permitting  the  heading  to  be  advanced.  The 
work  began  with  sinking  a  shaft  38  feet  in  outside  diameter, 


8       SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

lined  with  4  feet  of  brick  work  to  a  depth  of  54  feet  below 
mean  high  water.  On  opposite  sides  of  the  shaft,  in  the  direc- 
tion of  the  length  of  the  tunnel,  false  pieces  of  elliptical  form, 
26  feet  high  and  24  feet  wide,  were  built.  These  were  to  be 
removed  to  permit  the  passage  of  the  tunnel.  An  air  lock, 
6  feet  in  diameter  by  15  feet  long,  was  attached  to  the  shaft 
cylinder  above  the  false  piece  on  the  east  side.  A  temporary 
working  entrance  to  the  tunnel  was  formed  of  eleven  rings, 
each  2  feet  wide,  but  of  different  diameters.  The  tops  of  these 
rings  were  in  the  same  horizontal  line,  forming  a  cone-shaped 
chamber  with  steps  of  18  inches  leading  to  the  air-lock. 

From  the  base  of  this  cone,  which  was  20  feet  in  diameter, 
two  parallel  single  track  tunnels  were  started.  As  the  largest 
ring  was  not  large  enough  to  take  in  both  tunnels,  a  ring  of  a 
diameter  equal  to  the  exterior  of  the  north  tunnel  was  built 
and  lined  with  2  feet  of  brick  work.  Regular  tunnel  work  was 
then  commenced.  Silt  was  excavated  till  the  top  center  plate 
of  a  new  ring  could  be  placed  and  bolted  to  the  one  behind; 
then  plates  were  bolted  to  either  side  of  this  top  plate  until 
the  ring  was  completed.  When  four  rings  of  plate,  equal  to 
10  feet  of  section,  had  been  placed,  and  the  heading  cleared  out, 
the  masonry  was  laid.  The  plates  were  of  quarter-inch  iron, 
2 1  feet  in  width  by  3^  feet  in  length,  flanged  on  all  four  sides 
with  angle  iron.  The  tunnels  were  18  feet  high  by  16  feet  wide, 
inside  dimensions. 

The  air  pressure  was  kept  about  equal  to  the  hydrostatic 
head,  amounting  to  18  pounds  at  the  shaft  and  increasing 
to  36  pounds  at  a  distance  of  1600  feet.  No  fixed  rule  could 
be  given  to  govern  the  air  pressure,  but  it  was  found  generally 
that  a  little  less  than  the  hydrostatic  pressure  at  the  axis  of  the 
tunnel  gave  the  best  results  under  ordinary  conditions.  The 
excavated  chamber  was  23  feet  in  diameter,  so  that  the  dif- 
ference of  water  pressure  between  the  top  and  bottom  of  the 
chamber  was  about  11  pounds  per  square  inch.  Under  these 
conditions  some  air  escaped  through  the  roof  and  some  water 
entered  through  the  bottom.  Excessive  pressure  resulted  in 
an  increased  discharge  of  air  through   the  roof,   causing  the 


THE   ORIGINAL  HUDSON  TUNNEL  9 

silt  to  dry  out  and  drop  into  the  tunnel.  If  this  mass  was  suf- 
ficient a  blow-out  and  consequent  flooding  resulted. 

When  the  north  tunnel  had  been  advanced  over  a  quarter 
of  a  mile  the  south  tunnel  was  started,  and  when  this  had  been 
carried  forward  some  distance  both  tunnels  were  bulkheaded; 
and  work  on  the  removal  of  the  temporary  entrance  was 
commenced. 

A  serious  blowout  occurred  in  July.  1880.  The  doors  of 
the  airlocks  had  become  wedged  by  falling  earth  and  plates, 
cutting  off  the  escape  of  the  men,  twenty  of  whom  were  drowned. 
This  accident  had  an  unfavorable  effect  upon  the  financial 
aspect  of  the  undertaking. 

The  New  York  end  was  started  by  sinking  a  timber  caisson 
48  by  29^  feet  to  a  depth  of  56  feet  below  high  water,  where  it 
was  fully  imbedded  in  sand.  Through  the  west  side  of  this 
caisson,  on  the  line  of  the  tunnel,  an  opening  was  cut  and  roof 
plates  of  the  tunnel  put  in  and  braced.  Plates  were  added 
till  a  section  12  feet  long  had  been  built,  when  an  iron  bulk- 
head was  constructed.  In  building  additional  sections  the 
same  system  was  adopted.  As  each  section  of  the  iron  tube 
was  completed  it  was  cleaned  out  and  the  brick  fining  laid. 
This  was  the  first  and  only  instance  of  building  a  subaqueous 
tunnel  in  sand  without  the  aid  of  a  shield. 

S.  Pearson  &  Son  of  England  assumed  the  contract  in  1888, 
Sir  John  Fowler  and  Sir  Benjamin  Baker  acting  as  consulting 
engineers.  The  shield  method  of  driving  was  adopted  and 
heavy  iron  plates  were  substituted  for  masonry.  The  light 
boiler  plate  lining  was  no  longer  required.  The  work  was 
stopped  through  lack  of  capital  and  unsuccessful  attempts 
were  made  at  various  times  to  resume  the  operations  until 
the  early  part  of  1902.  In  that  year  the  franchise  and  property 
of  the  tunnel  company  were  acquired  by  the  New  York  and  New 
Jersey  Railroad  Company,  and  operations  were  again  started.  In 
1905  the  New  York  and  Xew  Jersey  Railroad  Company  disposed 
of  their  interests  to  the  Hudson  Company,  who  have  since  com- 
pleted the  tunnels.  The  completion  of  this  work,  which  is  now 
known  as  the  McAdoo  System,  is  described  in  another  chapter. 


CHAPTER   III 

THE   EAST  RIVER   GAS  TUNNEL 

The  first  completed  tunnel  under  the  East  River,  that  of 
the  East  River  Gas  Company,  for  the  transmission  of  illuminat- 
ing gas  from  the  gas  works  on  Long  Island  for  distribution 
throughout  Manhattan,  was  of  unusual  interest  and  importance 
in  that  its  successful  completion  demonstrated  the  entire  pos- 
sibility of  constructing  similar  tunnels  under  the  same  water- 
way wherever  they  may  be  required;  and  also  in  that  the  prog- 
ress of  the  work  revealed  the  pecuUar  conditions  and  the  special 
difficulties  which  might  be  expected  to  be  encountered  in  similar 
undertakings  in  the  same  neighborhood. 

This  tunnel  was  not  as  large  in  section  as  would  be  required 
for  a  standard  railroad,  or  even  for  trolley  cars  and  general 
traffic,  but  it  was  still  large  enough  to  reveal  all  the  difficulties 
which  a  larger  construction  would  have  involved.  The  rock 
section  was  required  to  be  8j  feet  high  and  lo  feet  wide,  and 
the  heading  was  driven  the  full  width.  The  location  of  the 
tunnel  is  from  Webster  Avenue,  Ravenswood,  Long  Island, 
under  both  channels  of  the  East  River,  with  Blackwell's  Island 
between  them,  to  Seventy-second  Street,  Manhattan.  The  roof 
grade  of  the  tunnel  was  40  feet  below  the  lowest  point  in  the  bed 
of  the  river,  which  was  in  the  west  channel  and  iii  feet  below 
mean  high  water  mark.  The  water  in  the  east  channel  was 
not  more  than  half  as  deep  as  that  in  the  west  channel  so  that 
the  depth  of  ground  over  the  tunnel  was  there  much  greater. 

Preliminary  investigation  revealed  bed  rock  on  both  sides 
of  the  river  only  a  few  feet  below  the  surface  and  also  on  the 
island;  and  drill  soundings  made  with  difficulty  in  both  channels 

10 


THE  EAST  RIVER  GAS  TUNNEL  11 

seemed  to  show  from  two  to  five  feet  of  sand  and  gravel  at  the 
bottom  and  then  solid  rock,  so  that  the  driving  of  the  tunnel 
was  expected  to  be  a  clean  and  uninterrupted  job  straight 
through  and  the  contract  for  the  job  was  placed  on  that 
basis. 

Work  was  begun  by  the  contractors,  McLaughlin,  Reilly 
&  Co.,  at  the  Long  Island  end  June  28,  1892.  Bed  rock  was 
found  92  feet  below  the  surface,  being  a  compact  gneiss  almost 
approaching  granite.  Work  commenced  on  the  New  York 
end  July  10.  The  rock  here  was  the  regular  micaceous  gneiss 
known  as  "  New  York  rock."  The  rock  in  the  New  York  shaft 
was  straight  grained  with  a  dip  of  about  10  degrees  from  the 
vertical,  striking  nearly  north  and  south  and  becoming  harder 
as  the  depth  increased.  No  water  or  any  abnormal  difiiculties 
were  encountered  and  the  bottom  of  the  shaft  was  reached  at 
the  end  of  October,  139I  feet  below  the  surface.  At  the  Long 
Island  shaft  the  progress  was  not  so  rapid.  The  rock  was  seamy 
and  much  water  was  encountered.  There  was  no  reliable  water 
supply  for  the  boilers  and  the  water  obtainable,  although  not 
salt,  was  entirely  unfit  for  use  and  there  were  numerous  stoppages 
during  the  entire  continuance  of  the  work  on  account  of  the 
water  supply. 

The  care  and  precision  with  which  the  line  was  laid  are 
indicated  by  the  fact  that  when  the  headings  met,  1678  feet 
from  the  New  York  shore,  the  lines  were  within  h  inch  of  each 
other  laterally  and  i\  vertically. 

Two  Ingersoll-Sergeant  compressors  were  installed  at  each 
end  of  the  tunnel,  and  drills  of  the  same  company  were  em- 
ployed throughout  the  work.  On  the  New  York  end  the 
driving  of  the  heading  proceeded  to  a  distance  of  348  feet,  when 
a  seam  of  decomposed  rock  was  struck,  a  straight  face  across 
the  heading.  After  advancing  into  this  9  feet  it  was  found 
unsafe  to  proceed,  the  ground  finally  having  reached  "  about 
the  consistency  of  soup."  A  steel  air  lock  6  feet  in  diameter  and 
10  feet  long,  was  made  and  fastened  solidly  in  the  rock.  Work- 
ing under  air  pressure  was  commenced,  the  initial  pressure 
being  35  pounds;   electric  lighting  was  installed. 


12      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

The  heading  was  enlarged  and  changed  to  a  circle  12  feet 
in  diameter.  The  tunnel  in  this  part  was  lined  as  it  advanced 
with  light  plates  of  wrought  iron  connected  with  angle  irons, 
and  12  inches  of  brick  work  was  laid  inside  the  plates.  One- 
half  of  the  thickness  of  the  brick  was  subsequently  removed 
and  a  lining  consisting  of  cast  iron  segments  bolted  together 
finished  the  job. 

The  working  air  pressure  was  ultimately  raised  to  48  pounds, 
which  was  higher  than  men  had  ever  worked  in  before,  and  they 
began  to  experience  serious  difficulty  in  continuing  the  work. 
Four  deaths  in  all  resulted  from  the  air  pressure,  and  there 
were  no  other  deaths  or  accidents  in  the  entire  progress  of  the 
work.  The  first  man  to  die  was  a  foreman.  The  second  man 
had  been  long  out  of  employment  and  was  in  very  low  condi- 
tion. He  died  in  the  air  lock  after  his  first  shift  of  two  hours. 
The  third  man  became  paralyzed  from  his  shoulders  down  and 
died  soon  after.  The  fourth  man  died  nearly  a  year  after  the 
others. 

In  connection  with  this  feature  of  the  work  the  following 
rules  for  men  working  in  compressed  air  were  formulated  by 
Dr.  Andrew  H.  Smith  of  the  Presbyterian  Hospital: 

1.  Never  enter  the  air  lock  with  an  empty  stomach. 

2.  Use  as  far  as  possible  a  meat  diet,  and  take  warm  coffee 
freely. 

3.  Always  put  on  extra  clothing  when  coming  out,  and 
avoid  exposure  to  cold. 

4.  Exercise  as  Httle  as  possible  during  the  first  hour  after 
coming  out,  and  lie  down  if  possible. 

5.  Use  intoxicating  liquors   sparingly.     Better  not   at   all. 

6.  Take  at  least  eight  hours  sleep  every  night. 

7.  See  that  the  bowels  are  evacuated  every  day. 

8.  Never  enter  the  lock  if  at  all  sick. 

9.  In  exit  from  the  air  lock,  the  time  occupied  should  be 
five  minutes  for  each  atmosphere  above  the  normal. 

The  earliest  injurious  effect  experienced  is  an  itching  caused 
by  air  globules  in  the  capillaries,  which  may  be  quickly  cured 
by  inducing  profuse  perspiration. 


THE  EAST  RIVER  GAS  TUNNEL  13 

The  "  bends,"  a  more  serious  trouble,  is  an  intense  rheumatic 
pain  in  the  joints  caused  by  air  globules  in  the  sockets. 

Paralysis  leaves  lasting  injury  and  is  usually  the  cause  of 
death  when  it  occurs. 

A  highly  steam  heated  dressing  room  was  found  beneficial, 
with  copious  supplies  of  hot,  strong  coflee. 

For  pressures  up  to  30  pounds  the  men  worked  two  shifts 
of  four  hours  each,  with  one  hour  of  rest  between.  For  the 
highest  pressure  the  men  worked  only  i|  hours  at  a  time,  and 
4^  hours  for  the  entire  day. 

The  information  herein  contained  is  mostly  abstracted  from 
the  report  of  the  chief  engineer,  Mr.  Charles  M.  Jacobs,  Mem. 
Inst.  C.E.,  Mem.  Inst.  M.E.  The  following  narration  of  a 
bit  of  experience  of  Sunday,  March  26,  1893,  is  quoted  from  the 
report. 

"  In  order  to  keep  an  exact  record  of  the  air  pressure  I  had 
fitted  up  an  Edison  automatic  recording  pressure  gage  with 
high  and  low  pressure  alarm  bells  attached.  The  foreman  of 
the  contractors  with  the  engineer  had  broken  the  lock  and 
removed  the  pencil.  The  fires  were  nearly  out  and  the  com- 
pressors were  stopping,  the  pressure  having  fallen  11  pounds. 
A  large  quantity  of  soft  ground  had  worked  into  the  heading, 
entailing  more  exercise  of  ingenuity  and  determination  to  get 
things  going  right  again.  A  great  cavity  had  washed  in  and 
the  water  was  bringing  it  down  continuously." 

In  the  progress  of  the  work  serious  troubles  occurred  with 
the  contractors,  who  finally  abandoned  the  entire  contract. 
At  one  point  they  had  to  be  restrained  by  injunction  from 
removing  their  compressors  at  a  critical  time.  The  air  pres- 
sure would  not  have  been  maintained  and  a  general  collapse 
might  have  resulted.     The  matter  became  a  subject  of  litigation. 

At  the  Long  Island  end  of  the  work  the  troubles  had  their 
own  individuahty.  Bad  and  insufiticient  water  for  the  boilers 
caused  frequent  stoppages,  while  it  was  essential  to  keep  the 
pumps  active  to  prevent  drowning  out.  The  first  soft  ground 
was  met  253  feet  from  the  shaft,  and  at  285  feet  a  green,  slimy, 
and  almost  liquid  material  began  oozing  out,  which  so  embar- 


14       SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

rassed  the  contractors  that  they  then  abandoned  the  work, 
allowing  the  heading  to  fill  with  water. 

The  stringency  of  the  money  market  in  1893  was  another 
incident  which  caused  a  cessation  of  all  operations  for  a  couple 
of  months. 

A  neighboring  picnic  place,  "  Jones's  Woods,"  took  fire 
and  with  it  was  destroyed  the  entire  plant  at  the  New  York 
end,  and  before  pumps  and  compressors  could  be  installed  the 
heading  was  drowned  out  again.  ^ 

The  time  of  greatest  anxiety,  difficulty  and  risk  was  when, 
in  advancing  the  shield  at  the  New  York  end,  a  shelving  bank 
of  rock  was  found  in  front  of  the  bottom  of  the  shield,  while 
at  the  top  was  the  softest  black  mud.  It  was  necessary  to 
blast  out  this  rock  in  the  floor  in  advance  of  the  shield  and  to 
get  through  the  bulkhead  which  had  been  put  in  when  the 
work  had  been  abandoned.  Direct  communication  was  opened 
with  the  river,  so  that  refuse  and  even  live  crabs  came  into 
the  tunnels.  The  leakage  of  air  was  so  great  that  both  com- 
pressors at  the  limit  of  their  speed  had  difficulty  in  maintaining 
the  pressure  of  48  pounds.  The  difficulties  continued  until 
the  shield  was  entirely  entered  into  the  black  mud,  when  the 
pressure  was  reduced  and  the  shield  was  advanced  at  the  rate 
of  6  feet  per  day.  The  shield  was  pushed  forward  by  twelve 
hydraulic  jacks  with  a  combined  thrust  of  600  tons.  The 
second  soft  place  extended  98  feet.  The  rock  ahead  was  badly 
seamed,  but  finally  became  solid  again  and  then  in  two  weeks 
loi  feet  and  94.6  feet  advance  respectively  was  made,  which 
rate  had  never  been  surpassed  in  that  class  of  rock. 

The  headings  met  July  11,  1894,  1676  feet  from  the  New 
York  shaft.  The  total  distance  from  shaft  to  shaft  was  2550 
feet,  so  that  two-thirds  of  the  length  was  driven  from  the  New 
York  end.  When  working  in  solid  rock  the  average  progress 
was  69  feet  per  week.  Bonuses  were  given  to  foremen  and  to 
some  of  the  gang  leaders. 

Considering  the  unexpected  difficulties  encountered  and  the 
delays  from  so  many  different  causes,  the  total  time  from  the 
beginning  to  the  completion  of  the  tunnel,  a  few  days  over  two 


THE  EAST  KIVER  GAS   TUNNEL  15 

years,  must  be  considered  remarkable,  and  could  only  have 
been  possible  with  constant  resourcefulness  and  untiring  push. 
After  the  ends  met  there  was  little  more  to  be  done  and  in  a 
very  short  time  a  36-inch  gas  main  was  laid  with  an  uninterrupted 
motor  car  track  at  the  side  of  it.— From  Compressed  Air 
Magazine. 


CHAPTER  IV 

MANHATTAN-BRONX  DIVISION  OF  THE  NEW  YORK  SUBWAY 

In  January,  1890,  the  contract  for  the  Manhattan-Bronx 
division  of  the  New  York  subway  was  awarded  and  the  work 
of  construction  was  undertaken  by  the  Rapid  Transit  Subway 
Construction  Company.  The  work  was  to  be  done  in  four 
sections,  as  follows: 

Section  i  extended  from  the  southern  terminus  at  City 
Hall  to  and  including  the  station  at  59th  Street  and  Broad- 
way; it  comprised  live  miles  of  four-track  subway. 

Section  2  included  all  railroad  from  the  north  end  of  the 
59th  Street  station  to  and  including  the  station  at  137th  Street 
and  Broadway;  and  on  the  east  side  from  the  junction  of 
103d  Street  and  Broadway  to  and  including  the  station  at 
135th  Street  and  Lenox  Avenue.  This  section  comprised  3.43 
miles  of  two-track  subway  and  0.51  mile  of  three-track  viaduct. 

Section  3  included  all  railroad  on  the  west  side,  northward 
from  the  station  at  137th  Street  and  Broadway,  to  and  includ- 
ing the  station  at  Fort  George;  and  on  the  east  side  from  the 
station  at  135th  Street  and  Lenox  Avenue,  to  and  including  the 
station  at  Melrose  Avenue.  This  comprised  4.32  miles  of  two- 
track  subway. 

Section  4  comprised  the  remainder  of  the  road,  from  Fort 
George  to  Kingsbridge  on  the  west  side  and  from  Melrose 
Avenue  on  the  east  side,  including  5.29  miles  of  two-track 
viaduct. 

The  prices  to  be  paid  were  as  follows: 

Section  i $15,000,0x50 

Sections  i  and  2 26,000,000 

Sections  i,  2  and  3 32,000,000 

Sections  i,  2,  3  and  4 35,000,000 

The  cost  of  equipment  was  estimated  at  $6,000,000. 

Note.  From  Report  of  the  Chamber  of  Commerce  of  New  York  State,  1905; 
The  New  York  Subway,  issued  by  the  Interborough  Rapid  Transit  Company. 

16 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


17 


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,  96th  SI. 
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Map  of  the  New  York  Rapid  Transit  Subway  in  Manhattan  and  The  Bron.x, 
with  Contour  of  the  Lenox  Avenue  Branch. 


18  MANHATTAN-BRONX  DIVISION 

Five  designs  were  adopted  in  the  construction  of  the  Man- 
hattan-Bronx Division  of  the  subway,  as  follows: 

For  a  length  of  10.6  miles  or  52.2  per  cent  of  the  total  length 
of  the  road,  the  typical  section  has  a  flat  roof  near  the  surface 
with  I-beams  connected  by  concrete  arches  forming  the  roof 
and  sides,  supported  by  bulb  angle  columns  between  the  tracks. 

In  the  Battery  Park  loop,  for  a  short  distance  on  Lenox 
Avenue  and  in  the  Brooklyn  portion  of  the  Brooklyn  extension 
(later  discussed),  a  flat  roof  of  reinforced  concrete  is  supported 
by  bulb  angle  columns  between  the  tracks. 

For  a  distance  of  4.6  miles  or  23  per  cent  of  the  total  length, 
concrete-lined  tunnel  was  used,  of  which  4.2  per  cent  was  con- 
crete-lined open  cut  work  and  the  remainder  rock  tunnel. 

An  elevated  road  on  a  steel  viaduct  was  used  for  about 
five  miles  or  24.6  per  cent  of  the  total  length. 

Under  the  Harlem  River,  and  under  the  East  River  for  the 
Brooklyn  extension,  cast  iron  tubes  were  used.  The  construc- 
tion of  the  typical  subway  has  been  carried  out  by  a  variety 
of  methods  adapted  to  the  different  situations  in  accordance 
with  the  views  of  the  sub-contractors  doing  the  work.  The 
work  was  done  in  open  excavation  by  the  "  cut  and  cover  " 
system.  The  distance  from  the  street  level  to  the  rock  surface 
below  determined  the  manner  of  excavating  trenches.  In  some 
places  the  rock  came  to  the  surface;  in  other  places  the 
subway  was  entirely  in  water-bearing  loam  or  sand.  The 
natural  difficulties  of  construction  were  increased  by  the  net- 
work of  sewers,  water  and  gas  mains,  steam  pipes,  pneumatic 
tubes,  electric  conduits,  etc.,  which  filled  the  streets.  The 
surface  roads  and  their  conduits  still  further  complicated  the 
problem. 

In  some  places  the  columns  of  the  elevated  roads  had  to  be 
shored  temporarily.  Where  the  subway  passed  close  to  the 
foundations  of  high  buildings  the  shoring  and  other  precau- 
tionary measures  to  insure  safety  were  both  intricate  and  costly; 
and  a  large  proportion  of  the  route  was  close  to  the  surface, 
which  entailed  the  removal  and  reconstruction  in  many  places 
of   the  underground  mains  and  ducts  and   of   the  projecting 


MANHATTAN-BRONX  DIVISION 


19 


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20 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


vaults  and  buildings,  and  required  the  underpinning  of  walls. 
Provision  also  had  to  be  made  for  the  maintenance  of  traffic 
upon  the  streets  under  which  the  subway  was  being  built. 
Small  sections  or  areas  of  these  streets  were  floored  or  bridged 
to  form  a  roadway  for  traffic  while  excavation  was  going  on 
beneath.  Where  the  rock  came  to  the  surface  it  was  necessary 
to  divert  the  electric  surface  roads  to  the  side  of  the  street; 
for  attempts   to   remove   the   rock   from   beneath   the   tracks 


Subway  Construction  at  Union  Square  and  Fourth  Avenue. 

destroyed  the  yokes  of  the  surface  road.  Open  trench  work 
was  adopted  where  the  roadway  was  sufficiently  wide  to  per- 
mit traffic  at  the  sides.  In  the  case  of  surface  tracks  overlying 
the  area  to  be  excavated  the  tracks  were  hung  from  the  lower 
chords  of  trusses  supported  at  their  ends  on  crib  work. 

Between  33d  and  42d  Streets  under  Park  Avenue,  between 
ii6th  and  120th  Streets  under  Broadway,  between  157th 
Street  and  Fort  George  under  Broadway  and  Eleventh  Ave- 
nue,  and  between  104th  Street  and  Broadway  under  Central 


MANHATTAN-BRONX   DIVISION 


21 


Park  and  Lenox  Avenue,  the  road  is  in  a  rock  tunnel  lined  with 
concrete.  The  section  on  the  west  side  between  157th  Street 
and  Fort  George  constitutes  the  second  longest  double-track 
rock  tunnel  in  the  United  States,  the  Hoosac  Tunnel  only 
exceeding  it  in  length. 

From  1 1 6th  Street  to  120th  Street  on  Broadway  the  tunnel 
is  372  ^eet  in  width — one  of  the  widest  concrete  arches  in  the 
world.    On  the  Lenox  Avenue  section  from  Broadway  and  103d 


Subway  Tunnel  Heading  at  116th  Street  and  Broadway:  Timbering  in  Soft 
Ground  Over  Rock. 

Street  to  Lenox  Avenue  and  iioth  Street  under  Central  Park, 
a  two-track  tunnel  was  driven  through  micaceous  rock  by 
taking  out  top  headings  and  tw^o  full-width  benches,  the  work 
being  done  from  two  shafts  and  one  portal.  All  drilling  for 
the  headings  was  done  by  an  eight-hour  night  shift,  using  per- 
cussion drills.  The  blasting  was  done  early  in  the  morning  and 
the  day  gang  removed  the  spoil,  which  was  hauled  to  the  shafts 
and  the  portal  in  cars  drawn  by  mules.      A  large  part  of  this 


22 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


rock  was  crushed  for  concrete.  The  concrete  floor  was  the 
first  part  of  the  hning  to  be  put  in  place.  Rails  were  laid  on 
it  for  a  traveler  having  molds  attached  to  its  sides,  against  which 
the  walls  were  built.  A  similar  traveler  followed  with  the  cen- 
tering for  the  arch  roof,  a  length  of  about  fifty  feet  being  com- 
pleted at  each  operation. 

On  the  Park  Avenue  section  from  34th  Street  to  41st 
Street  two  separate  double-track  tunnels  were  driven  below, 
and  one  on  either  side  of,  a  double-track  electric  railway  tunnel. 


Open  Cut  Subway  Construction  in  Central  Park,  Lenox  Avenue  Branch. 


This  work  was  done  from  four  shafts,  one  at  each  end  of  each 
tunnel.  At  first  top  headings  were  driven  at  the  north  end  of 
both  tunnels  and  at  the  south  end  of  the  west  tunnel;  at  the 
south  end  of  the  east  tunnel  a  bottom  heading  was  driven.  The 
system  of  driving  at  the  south  end  of  the  west  tunnel  was  later 
changed  from  a  top  to  a  bottom  heading.  The  rock  in  this 
section  was  irregular  and  the  inclination  of  the  strata  gave 
rise  to  serious  danger  from  slips. 


MANHATTAN-BRONX  DIVISION  23 

The  headings  of  the  west  tunnel  met  in  February  and  those  of 
the  east  tunnel  in  March,  1902.  The  enlargement  of  the  tunnels 
to  the  full  section  was  then  commenced.  A  disturbance  above 
the  surface  of  the  east  tunnel  resulted  in  damage  to  several 
house  fronts.  The  portion  of  tunnel  affected  was  bulkheaded 
at  each  end,  packed  with  rubble  and  grouted  with  Portland 
cement  mortar  injected  under  pressure  through  pipes  sunk  from 
the  street  surface.  When  the  interior  was  firm  the  tunnel  was 
re-driven,  using  much  the  same  methods  employed  in  earth  tun- 
nels where  the  arch  lining  is  built  before  the  central  cone  has  been 
removed.  To  avoid  further  settlement  of  the  earth  the  work  was 
done  slowly.  When  the  lining  had  been  completed  Portland 
cement  grout  was  again  injected  under  pressure  through  holes  left 
in  the  roof  until  further  movement  of  the  fill  above  was  prevented. 

The  tunnel  between  157th  Street  and  Fort  George,  already 
referred  to  as  the  second  longest  two-track  tunnel  in  the 
United  States,  was  put  through  in  a  short  time  and  without 
any  special  difficulty.  The  tunnel  was  driven  from  two  portals 
and  two  shafts,  the  latter  at  i68th  and  181st  Streets.  The 
heading  was  carried  north  and  south  from  each  shaft. 

The  Harlem  River  is  crossed  by  a  tunnel  of  twin  single- 
track  cast-iron  cylinders  16  feet  in  diameter.  The  approaches 
on  both  sides  are  double-tracked  concrete  arch  structures.  The 
total  length  of  the  section  is  1500  feet,  of  which  641  feet  are 
of  the  cast-iron  cylinder  construction.  Instead  of  employing 
the  usual  methods  by  the  use  of  shields  and  compressed  air, 
these  subaqueous  tunnels  were  formed  by  dredging  a  trench  in 
the  bed  of  the  river,  in  which  a  caisson  was  built,  within  which 
the  excavation  was  made.  The  bed  of  the  Harlem  River  at 
this  point  is  of  mud,  silt  and  sand,  much  of  which  was  so  nearly 
fluid  that  it  was  removed  by  a  jet  process.  The  maximum 
depth  of  excavation  was  about  fifty  feet.  The  trench  was  50 
feet  wide  and  carried  to  a  grade  of  39  feet  below  low  water, 
this  grade  being  about  10  feet  above  the  subgrade  of  the  tunnel. 
The  War  Department  required  that  there  be  a  depth  of  20  feet 
over  the  tunnel  at  low  water  and  that  during  construction  half 
of  the  width  of  the  river  should  be  left  free  for  navigation. 


24      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

To  support  a  working  platform  three  rows  of  piles  were  driven 
on  each  side  of  the  trench  from  the  west  bank  to  the  middle 
of  the  river,  there  being  38  feet  in  the  clear  between  the  plat- 
forms. A  pile  foundation  was  then  made  over  the  area  to  be 
covered  by  the  subway.  The  piles  were  driven  with  6  feet 
4  inches  transversely  and  8  feet  longitudinally  between  centers. 
They  were  then  cut  off  1 1  feet  above  the  center  line  of  each  tube 
and  capped  with  12-inch  square  timbers.     A  caisson  in  which 


Concrete  Arch  Subway  Construction  in  Open  Cut. 

to  excavate  the  remaining  material  and  place  the  iron  and  con- 
crete was  formed  of  12-inch  sheet  piles  for  the  sides  and  a  heavy 
timber  roof.  As  a  guide  and  steadiment  for  the  sheet  piling 
which  formed  the  sides  of  the  caisson,  a  frame-work  was  built 
and  sunk  over  the  pile  foundations.  Transverse  trusses  were 
connected  longitudinally  at  their  outer  ends  by  eight  timbers 
12  inches  square,  so  arranged  that  two  timber  stringers, 
separated  to  permit  the  passage  of  and  to  form  a  guide  for  the 
sheet  piles,  were  bolted  to  the  upper  and  lower  chords  at  each 
end.    The  sheathing  was  driven  to  a  depth  of  10  to  15  feet  below 


MANHATTAN-BRONX  DIVISION  25 

the  bottom  of  the  hnished  tunnel.  The  roof,  formed  of  three 
courses  of  12-inch  square  timbers,  separated  by  a  2-inch  plank 
and  thoroughly  caulked,  was  then  floated  into  position  over 
the  piles,  loaded  with  earth  and  sunk.  Three  timber  shafts, 
7X17  feet  in  plan,  passed  through  this  roof.  Work  in  this 
caisson  was  carried  on  under  air  pressure,  part  of  the  spoil 
being  blown  out  by  water  jets  and  the  remainder  removed 
through  the  air-locks  in  the  shafts.  When  the  excavation  had 
been  completed  the  piles  were  braced,  the  concrete  and  cast- 
iron  lining  put  in  place,  and  the  piles  cut  off  as  the  concrete 
bed  was  laid  up  to  them. 

The  eastern  half  of  this  tunnel  was  a  modification  of  the  plan 
just  described.  The  side  walls  of  the  caisson  were  formed  of 
sheet  piling,  but  for  a  roof  the  permanent  upper  half  of  the 
tunnel  of  iron  and  concrete  was  used.  The  trench  was  dredged 
nearly  to  subgrade.  Steel  pilot  piles  with  water  jets  were 
driven  in  advance  of  the  wooden  sheet  piles.  If  boulders  were 
encountered  they  were  drilled  and  blasted.  The  steel  piles 
were  pulled  by  a  hoisting  engine  and  the  wooden  piles  driven 
in  their  place.  When  the  piling  was  finished  a  pontoon  35 
feet  by  106  feet  and  12  feet  deep  was  built  between  the  working 
platforms.  Upon  a  false  deck  or  floor  the  upper  half  of  the  cast- 
iron  shells  was  assembled,  their  ends  closed  by  steel  diaphragms, 
and  the  whole  covered  with  concrete.  The  pontoon  was  then 
submerged  several  feet,  parted  at  the  center  and  each  half  drawn 
endwise  from  beneath  the  floating  top  of  the  tunnel.  The  lat- 
ter was  then  loaded  and  carefully  sunk  in  place,  the  connec- 
tion with  the  shore  section  being  made  by  a  diver  and  access 
through  the  roof  being  provided  by  a  special  opening.  When 
in  place  men  entered  through  the  shore  section,  cut  away  the 
floor  or  wooden  bottom  and  completed  the  caisson  so  that 
work  could  proceed.  Three  of  these  caissons  were  required 
to  complete  the  east  end  of  the  crossing. 

The  construction  of  the  approaches  to  the  sub-river  tunnel 
was  carried  out  between  heavy  sheet  piling.  The  excavation 
was  very  wet  and  in  places  over  40  feet  in  depth. 

The  following   data   cover   the   essential  features   involved 


26  SUBWAYS  AND  TUNNELS   OF  NEW  YORK 

in  the  building  of  the  Manhattan-Bronx  section  of  the  subway, 
the  approximate  quantities  of  excavation  and  materials  being 
from  the  chief  engineer's  report: 

The  total  length  of  this  section  of  the  subway  is  109,570  feet. 

The  total  amount  of  excavation  was  2,990,016  cubic  yards  of 
which  1.700,228  cubic  yards  were  earth,  921,182  cubic  yards  were 
open  cut  rock  work,  and  368,606  cubic  yards  were  rock  tunnel. 


Cameron  Pump  for  Drainage  in  Harlem  River  Tunnel,   New  York  Subway. 

The  cost  of  excavating  was  about  one-third  of  the  total 
amount  of  the  contract.  The  time  required  for  excavating  was 
two-thirds  of  the  time  allotted  for  the  completion  of  the  job. 

The  quantities  of  the  principal  materials  used  in  construc- 
tion were  approximately  as  follows:  steel,  65,000  tons;  cast 
iron,  8,000  tons;  concrete,  489,122  cubic  yards;  brick,  18,519 
cubic  yards;    water-proofing  materials,   775.795  square  yards. 

The  total  length  of  track  is  305,000  feet,  of  which  245,000 
feet  are  underground  and  60,000  feet  above  ground.  The 
contract  time  was  four  and  one-half  years. 


CHAPTER  V 

BROOKLYN-MANHATTAN  DIVISION  OF  THE  NEW  YORK 
SUBWAY 

In  September,  1902,  the  contract  for  the  Brooklyn-Manhattan 
branch  of  the  subway  was  awarded  to  the  Rapid  Transit  Sub- 
way Construction  Company  for  83,000,000.  The  route  to  be 
followed  was  to  be  from  the  junction  of  Park  Row  under  Broad- 
way, Bowling  Green,  Battery  Place,  State  Street  and  Battery 
Park,  with  a  loop  under  Battery  Park  and  Whitehall  Street. 
From  there  it  was  to  pass  under  the  East  River  to  Furman  Street, 
Brooklyn,  and  thence  under  Joralemon  and  Fulton  Streets  and 
Flatbush  Avenue  to  the  junction  of  Flatbush  and  Atlantic 
Avenues.  The  entire  line  is  underground.  At  the  Battery 
the  Brooklyn  line  passes  under  the  ^Manhattan  line  to  avoid 
a  grade  crossing.  The  estimated  cost  of  road  and  equipment 
was  from  $8,000,000  to  810,000,000. 

Three  types  of  construction  were  used  in  the  Manhattan- 
Brooklyn  Division,  as  follows: 

T^-pical  fiat-roof  steel  beam  subway  from  the  Post  Office 
to  Bowling  Green. 

Typical  reinforced  concrete  subway  in  Battery  Park,  Man- 
hattan, and  from  Clinton  Street  to  the  terminus  in  Brooklvn. 

Two  single-track  cast-iron  hned  tubular  tunnels  from  Battery 
Park  under  the  East  River  and  under  Joralemon  Street  to  Clin- 
ton Street,  Brooklyn. 

Under  Broadway,  ^Manhattan,  the  work  was  through  sand. 
The  congested  surface  traffic,  the  net-work  of  sub-surface  struc- 
tures, and  the  high  buildings  adjacent,  made  this  one  of  the 
most  difficult  portions  of  the  road  to  build.  Because  of  the 
heavy  surface  traffic  it  was  required  that  during  construction 
the  street  should  be  maintained  in  a  condition  which  would 

27 


28 


SUBWAYS  AXD  TUNNELS  OF  NEW  YORK 


not  impede  this  traffic  during  the  day  time.  This  was  pro- 
vided for  by  making  openings  in  the  sidewalks  near  the  curb 
at  two  points  and  erecting  temporary  working  platforms  over 
the  street,  i6  feet  from  the  surface. 

Excavation  was  done  by  the  ordinary  drift  and  tunnel 
method.  The  excavated  material  was  hoisted  from  the  open- 
ings to  the  platforms  and  discharged  into  wagons.  On  the  street 
surface,  over  and  in  advance  of  the  excavation,  temporary  plank 


Drilling  and  Mucking  in  East  River  Subway  Tunnel. 

decks  were  placed  and  maintained  during  the  drifting  and 
tunnehng  operations,  and  after  the  permanent  subway  structure 
had  been  erected  up  to  the  time  when  the  street  surface  was 
permanently  restored.  As  the  roof  of  the  subway  was  only  five 
feet  from  the  street  surface,  gas  and  water  mains  and  conduits 
had  to  be  arranged  for.  These  were  carried  temporarily  on  a 
trestle  work  over  the  sidewalks  and  when  the  subway  structure 
was  completed  they  were  restored  to  their  former  position. 


THE   BiiUUKLYN-MANHATTAN   DIVISION 


29 


From  Bowling  Green,  south  along  Broadway  and  State 
Street  and  in  Battery  Park,  where  the  subway  was  in  reinforced 
concrete,   the   "  cut  and  cover  "  method  was  employed,   the 


Driving  Sheet  Piling  with  an  Ingersoll-Rand  Sheet  Pile  Driver   on  Subway 
Construction  in  Brooklyn. 


elevated  and  surface  railway  structures  being  temporarily  sup- 
ported by  wooden  and  steel  trusses  and  permanently  supported 
by   foundations  resting  on   the  subway   roof.     From   Battery 


30      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

Place,  south  along  the  loop,  the  greater  portion  of  the  excava- 
tion was  below  mean  high-water  level,  and  necessitated  the  use 
of  heavy  tongue-and-groove  sheathing  and  the  continuous 
operation  of  two  centrifugal  pumps  to  keep  the  work  dry. 

The  tubes  or  tunnels  under  the  East  River,  including  the 
approaches,  were  each  6544  feet  in  length.  They  were  formed 
of  cast-iron  sections  bolted  together  and  had  an  inside  diameter 


Ingersoll-Rand  Rock  Drills  in  Heading  of  One  of  the  East  River  Subway 

Tunnels. 

of  15I  feet.  They  were  reinforced  by  grouting  outside  of  the 
plates  and  lined  inside  with  beton  to  the  depth  of  the  flanges. 
From  the  Manhattan  side  to  the  middle  of  the  East  River 
the  tunnels  were  in  rock  and  the  ordinary  rock  tunnel  drift 
method  was  employed,  the  work  being  carried  on  under  air 
pressure.  On  the  Brooklyn  side  beneath  the  river  the  formation 
was  sand  and  silt.  Four  shields  weighing  51  tons  each  were 
used  and  a  hydraulic  pressure  of  about  2000  tons  provided  to 


THE  BROOKLYN-MANHATTAN   DIVISION  31 

force  them  forward;  two  shields,  working  from  Garden  Place 
toward  the  center  of  the  river,  were  operated  under  air  pres- 
sure in  water-bearing  sand.  The  river  tubes  have  a  3.1  per 
cent  grade,  and  at  the  deepest  point  in  the  middle  of  the  river 
the  depth  is  about  94  feet  below  mean  high  water. 

The  typical  subway  of  reinforced  concrete  from  Clinton 
Street  to  the  terminus  at  Flatbush  Avenue  was  constructed 
by  the  method  already  described  in  connection  with  the  Man- 
hattan-Bronx Division.  From  Borough  Hall  to  the  terminus 
the  route  of  the  subway  is  directly  below  an  elevated  structure, 
which  was  temporarily  supported  by  timber  bracing  having  its 
bearing  on  the  street  surface  and  upon  the  tunnel  timbers. 
Permanent  support  was  provided  by  means  of  masonry  piers 
built  upon  the  roof  of  the  subway  structure. 

Along  this  portion  of  the  route  are  surface  electric  roads 
operated  by  an  overhead  trolley  on  tracks  of  the  ordinary  tie 
construction.  Little  difficulty  was  experienced  in  taking  care 
of  these  during  the  construction  of  the  subway.  Work  was 
carried  on  day  and  night,  the  excavation  being  expedited  by 
using  flat  cars  on  the  surface  trolley  roads  for  removing  the 
spoil.  Spur  tracks  were  built  for  this  purpose  and  most  of  this 
removal  was  done  at  night. 


CHAPTER   VI 

COMPRESSED   AIR    IX  THE    SUBWAY   CONSTRUCTION:     COST   OF 
EXCAVATION   IN   THE   NEW   YORK   SUBWAY 

The  original  plan  of  the  general  contractor  on  the  New  York 
subway  work,  Mr.  John  B.  McDonald,  was  to  install  air  com- 


^■•■v^ 


IngersoU-Rand  Corliss  Compressor  Used  in  Subway  Construction  at  the 
Batter}'  Park  Plant.  This  Compressor  was  one  of  those  used  in  build- 
ing the  Jerome  Park  Reservoir. 

pressing  plants  at  convenient  points  along  the  line  of  construc- 
tion and  to  dispose  of  the  air  power  to  the  sub-contractors. 
This  project,  however,  was  not  carried  out.  The  sub-contractors 
installed  their  own  compressor  plants,  either  as  individuals 
or  by  a  number  of  them  uniting  to  build  a  plant  for  their  own 

32 


COMPRESSED  AIR  IX  THE  SUBWAY  CONSTRUCTION  33 

use.  The  installation  and  use  of  central  air  compressing  plants 
to  provide  power  for  the  work  may  be  accepted  as  the  factor 
that  made  possible  the  building  of  the  subway  within  the 
specified  limits  of  time  and  cost.  It  is  to  be  regretted  that  no 
record  was  kept  of  the  actual  cost  of  operation  of  these  plants. 
Nor  were  there  any  steam  plants  working  under  similar  con- 
ditions with  which  comparison  could  be  made.  There  can  be 
no  doubt,  however,  that  the  advantages  of  compressed  air 
were  a  controlling  influence  in  hastening  this  important  work. 
To  illustrate  the  advantages  of  a  central  air  compressing  plant 
over  the  use  of  scattered,  direct  steam  driven  machines,  the 
following  comparison  is  given  showing  the  decrease  in  operating 
costs  secured  by  converting  the  steam  plants  of  the  Gray 
Canon  Quarries  near  Cleveland,  0.,  to  a  centraHzed  compressed 
air  plant.  The  table  given  below  is  a  comparison  of  average 
daily  fuel  and  labor  charges  against  the  power  system  during 
the  month  of  April,  1903,  when  operating  by  steam  and  during 
the  corresponding  month  of  1904,  when  operating  by  compressed 
air. 


Coal  consumption 

Labor     and     attendance, 

channelers 

Labor     and     attendance, 

drills 

Firemen  at  hoists 

i'iremen    at    pumps    and 

drill  boilers 

Firemen  at  mill,  12 -hour 

shift 

Boiler  repair  gang 

Locomotive  repair  and 

rental 

Coke  for  reheaters 

Total   charge,    labor   and 

fuel 


50  tons  run-of-mine 
at  $2  $100.00 

16  machines  at  $10     160.00 


15  machines  at  I 
9  men  at  $1.25 

2  men  at  $2 

2  men  at  $1.25 


45.00 
1 1. 2:; 


4.00 


2.50 
5.00 


15+    tons    slack    at 
$1.60  S  24.80 

12  machines  at  $10     120.00 


9  machines  at   $3       27.00 


$337-75 


5172.80 


The  total  daily  saving  in  labor  and  fuel  by  means  of  com- 
pressed air  was  $164.95,  corresponding  to  a  total  saving  in  a 
year  of  300  days  of  $49,485.00. 


34      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

The  reduction  in  the  number  of  machines  operated  in  1904 
is  due  to  the  fact  that  a  high  and  constant  air  pressure  was 
always  available  and  enabled  the  lesser  number  of  machines 
to  do  more  work  than  was  performed  by  the  greater  number 
in  1903,  when  operating  under  the  lower  and  fluctuating  steam 
pressure.  It  is  assumed  in  the  table  that  the  minor  charges 
for  lubrication  and  waste  are  the  same. 

The  coal  consumption  was  a  matter  of  absolute  record. 
In  1903,  run-of-mine  coal  was  used,  delivered  to  31  boilers,  and 
broken,  scattered  and  wasted  in  cartage.  In  1904  slack  coal 
was  handled,  at  minimum  cost. 

Another  fact  worthy  of  note  is  that  the  steam  plants  replaced 
by  the  new  air  system  were,  in  most  cases,  operating  under 
conditions  of  average  fuel  and  steam  economy.  The  boilers  at 
the  hoists  were  of  good  tubular  type,  in  standard  brick  settings 
and  well  housed.  The  channelers  carried  their  own  boilers  of 
standard  locomotive  type.  Yet  even  with  these  favorable 
conditions  for  fuel  economy  the  saving  in  coal  consumption 
has  been  as  indicated  in  the  table  above.  The  tabulated  com- 
parison is  a  statement  of  fact,  but  it  fails  to  bring  out  two  points 
of  vital  importance,  viz.,  the  output  of  rock,  when  using  air, 
was  greater  than  when  using  steam;  and  this  increased  output 
was  secured  with  a  force  reduced  by  75  men.  Figuring  these 
men  at  the  average  daily  wage  paid,  the  daily  saving  already 
shown  is  brought  up  to  $275.00. 

The  result  is  due  to  the  fact  that  a  full  working  day  of  ten 
hours  is  secured.  When  the  throttles  are  opened  a  full  working 
pressure  is  available  and  maintained  throughout  the  working 
day.  There  is  no  delay  in  starting  due  to  fluctuating  boiler 
pressure.  There  is  no  labor  employed  in  wheeling  coal,  in 
moving  water  barrels  and  pipe  to  keep  pace  with  machines. 
There  is  no  steam  or  smoke  settling  in  the  work  and  inter- 
fering with  the  hoisting.  There  is  no  water  to  be  blown  out 
or  draining  gangs  to  look  after  the  pipes  to  avoid  freezing. 
The  working  conditions  are  in  every  way  improved. 

Cost  of  Rock  Excavation  in  Open  Cut:  New  York  Subway. 
The  results  here  given  were  secured  under  fair  average  conditions. 


COSTS   OF  EXCAVATIOX  IN  NEW  YORK   SUBWAY        35 

using  air  driven  rock  drills,  loading  the  spoil  into  self-dumping 
buckets  carried  by  cablcways,  and  dumping  into  wagons. 

The  cost  of  drilling,  blasting  and  disposing  of  the  spoil  was, 
in  mica  schist,  from  $2.25  to  $2.40  per  cubic  yard,  varying  with 
the  length  of  haul  and  the  depth  of  cut.  This  high  cost  per 
cubic  yard  was  due  to  inefficient  labor,  to  the  restriction  of  city 
ordinances  limiting  the  amount  of  explosive  used  at  a  blast, 
and  to  the  great  amount  of  trimming  and  sledging  of  rock. 

The  average  scale  of  wages  was,  for  an  8-hour  shift, 
as  follows: 

Foremen $3.50  to  $4.00 

Laborers i  .50 

Teams  and  drivers 4.50 

Drillers 2.75 

Drillers'  helpers 1.50 

Hoist  runners 3.00 

Compressor  engineers 4.00 

Firemen 2.00 

Carpenters 3.50 

Timber  handlers 2.00 

Smiths 2.75 

Smiths'  helpers 1.50 

Water  boys 75 

In  the  cost  per  cubic  yard  as  here  given  allowance  has  been 
made  for  all  charges,  including  interest  and  depreciation. 

The  depth  of  excavation  was  from  twenty-five  to  forty  feet 
and  the  average  width  about  forty  feet.  Laborers  handled 
and  loaded  something  less  than  two  cubic  yards  per  shift;  this 
small  performance  to  be  accounted  for  by  the  sledging  and  plug- 
and-feather  work  required  after  blasting,  to  make  the  rock  of 
a  size  that  could  be  loaded  into  the  buckets  by  hand.  The  cost 
of  hauHng  about  one  mile  was  from  55  to  65  cents  per  cubic  yard. 
The  average  weight  of  40  per  cent  dynamite  used  per  cubic 
yard  was  three-fifths  of  a  pound,  dynamite  costing  12  j  cents  per 
pound. 


36      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

Cost  of  Earth  Work:  New  York  Subway.  The  earth  exca- 
vation in  the  lower  part  of  the  city  was  usually  performed 
under  the  most  difficult  conditions.  It  was  required  that  the 
street  traffic  should  not  be  interfered  with  during  the  day  time; 
that  surface  car  tracks  should  be  diverted  or  supported;  and 
that  the  net-work  of  mains,  conduits  and  sewers  should  be  kept 
operating  during  construction. 

The  cost  of  earth  excavation  under  these  conditions  was 
from  $3.50  to  $3.70  per  cubic  yard.  In  places  where  the  work 
was  in  sand,  the  cost  of  shoring  and  supporting  the  mains,  pipes 
and  conduits  was  50  cents  per  cubic  yard.  In  the  sections 
in  the  upper  part  of  the  town  where  the  traffic  was  less  and  the 
conditions  more  favorable,  the  cost  varied  between  75  and  95 
cents  per  cubic  yard.  This  was  in  earth,  ploughed  and  shoveled 
into  wagons,  the  wagons  being  pulled  out  of  the  cut  by  power 
or  snatch  teams. 

Under  conditions  where  the  surface  tracks  required  more 
support,  where  the  mains  and  conduits  were  more  numerous, 
and  where  the  spoil  was  dumped  at  sea,  the  cost  increased  to 
$1.25  to  $1.60  per  cubic  yard.  The  charge  for  hauling  to  sea 
by  barge  was  60  cents  per  wagon  load,  equivalent  to  about  30 
cents  per  cubic  yard.  The  contractors  were  paid  from  $2.00 
to  $2.50  per  cubic  yard  according  to  the  difficulties  of  excavation. 

Cost  of  Concrete :     New  York  Subway. 

In  foundations $4.50  to  $4.75  per  cubic  yard 

Roof  and  side  arches 7.50  to    8.00  per  cubic  yard 

Average  cost  per    cubic    yard   in 
arches,  foundations  and  covering    6.00 

Cost  of  Brick  Work :  New  York  Subway. 
In  backing $10.50  to  $11.00  per  cubic  yard 


CHAPTER   VII 

THE    PENNSYLVANIA    RAILROAD    DEVELOPMENTS  IN  AND  NEAR 
NEW  YORK   CITY 

The  North  River  Bridge  Company  projected  the  building 
of  a  great  suspension  bridge  across  the  North  or  Hudson  River 
to  enable  all  of  the  railroads  terminating  on  the  west  shore  of 
the  river  to  enter  New  York  City  at  the  foot  of  West  Twenty- 
third  Street.  The  Pennsylvania  Railroad  Company  gave  this 
project  its  support  by  agreeing  to  pay  its  pro  rata  share  for  the 
use  of  the  bridge,  but  the  other  railroads  declined  to  participate 
and  the  plan  was  abandoned. 

The  Pennsylvania  Railroad  having  acquired  control  of  the 
Long  Island  Railroad,  and  having  decided  to  establish  terminal 
facilities  in  New  York  City  proper,  undertook  the  project  of 
connecting  New  Jersey,  ^Manhattan  Island  and  Long  Island 
by  a  system  of  tunnels.  New  operating  conditions,  resulting 
from  the  application  of  electric  traction  to  the  movement  of 
heavy  railroad  trains,  which  were  initiated  in  tunnel  operation 
by  the  Baltimore  &  Ohio  Railroad  and  subsequently  studied 
and  adopted  by  railroads  in  Europe,  had  eliminated  the  dif- 
ficulties of  ventilation  connected  with  steam  traction  through 
tunnels  and  also  made  possible  the  use  of  grades  which  had 
been  practically  prohibitive  with  the  steam  locomotive. 

Under  the  new  plan  the  main  Hne  of  the  Pennsylvania 
Railroad  connects  with  the  tunnel  system  by  a  surface  Hne 
beginning  near  Newark,  N.  J.,  which  crosses  the  Hackensack 
]Meadows,  passes  through  Bergen  Hill  and  under  the  North 
River,  Manhattan  Island,  and  East  River  in  tunnels,  to  a 
large  terminal  yard  known  as  Sunnyside  Yard  in  Long  Island 
City 

37 


38 


SUBWAYS  AND   TUNNELS  OF    NEW   YORK 


THE   PEXXSYLVAXIA  RAILROAD   DEVELOPMENTS        39 

The  estimated  cost  of  the  New  York  tunnel  extension  and 
station,  including  the  interchange  yards  at  Harrison,  X.  J.,  and 
Sunnyside,  L.  I.,  was  Sioo, 000,000. 

This  system  is  essentiall}-  one  for  handUng  passenger  traffic, 
but  the  Pennsylvania  Railroad  has  not  only  the  legal  power 
but  also  the  facilities  for  making  it  a  through  route  for  freight 
if  desired.  The  requirements  include  handhng  the  heaviest 
through  express  trains  as  well  as  the  more  frequent  and  Ughter 
trains  for  local  service.  The  following  summary  of  the  various 
divisions  of  the  hne  will  give  a  comprehensive  idea  of  the  general 
features  of  the  project. 

The  ^Meadows  division  includes  the  interchange  yard  at 
Harrison,  near  Newark,  X.  J.,  adjoining  the  tracks  of  the  present 
X"ew  York  division  of  the  Pennsylvania  Railroad.  It  also 
includes  a  double-track  railroad  across  the  Hackensack  meadows 
to  the  west  side  of  Bergen  Hill,  a  total  distance  of  6.04  miles. 
The  construction  throughout  this  division  is  embankment  and 
bridge  work. 

The  X'orth  River  division  commences  at  the  west  side  of 
Bergen  Hill  and  passes  through  the  hill  in  two  single-track  rock 
tunnels  to  a  large  permanent  shaft  at  Weehawken,  near  the 
west  shore  of  the  North  River;  and  thence  eastward  a  distance 
of  224  feet  to  the  Weehawken  shield  chamber.  It  then  passes 
under  the  Xorth  River  through  two  cast  iron,  concrete-lined, 
single-track  tunnels  having  an  outside  diameter  of  23  feet,  to  a 
point  under  Thirty-second  Street  near  Eleventh  Avenue,  in  X'ew 
York  City.  It  continues  thence  through  two  single  track  tunnels 
of  varying  cross-section,  partly  constructed  by  the  cut-and-cover 
method,  to  the  east  side  of  Tenth  Avenue.  Here  it  enters  the 
station  yard  and  terminates  at  the  east  building  line  of  X^inth 
Avenue.  The  work  in  this  division  includes  the  station  yard 
excavation  and  walls  from  Tenth  Avenue  to  Ninth  Avenue, 
and  the  retaining  walls  and  temporary  underpinning  of  X'inth 
Avenue.  The  aggregate  length  of  line  in  this  division  is  2.76 
miles. 

The  X'ew  York  Terminal  Station  and  its  approaches  extend 
from  the  east  Hne  of  Tenth  Avenue  eastward  to  a  point  in  Thirty- 


40      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

second  and  Thirty-third  streets,  distant  respectively  292  feet 
and  502  feet  eastward  from  the  west  hne  of  Seventh  Avenue. 
This  division  includes  also  the  construction  of  subways  and 
bridges  for  the  support  of  Thirty-first  and  Thirty-third  streets 
and  Seventh,  Eighth  and  Ninth  avenues.  Work  classified 
under  this  division  comprises  also  the  Terminal  Building  between 
Seventh  and  Eighth  avenues;  the  foundations  for  the  Post 
Ofhce  to  be  erected  west  of  Eighth  Avenue;  the  service  power 
house  in  Thirty-first  Street  between  Seventh  and  Eighth  avenues; 
the  power  house  in  Long  Island  City;  and  the  traction  system, 
tracks,  signals  and  miscellaneous  facihties  required  in  the  phys- 
ical construction  of  the  entire  terminal  railroad  ready  for 
operation. 

The  terminal  station  is  of  steel  skeleton  construction  with 
masonry  curtain  walls,  all  supported  by  a  system  of  columns 
reaching  to  rock  foundation.  The  building  covers  two  city 
blocks  and  one  intersecting  street  and  has  an  area  of  about 
eight  acres.  It  is  774  feet  long,  433  feet  wide,  with  an  average 
height  above  the  street  of  69  feet  and  a  maximum  of  153  feet. 
The  main  waiting  room  is  277  by  103  feet  and  150  feet  high. 
The  concourse  is  340  feet  by  210  feet  in  size. 

The  level  of  the  track  system  below  the  street  surface  varies 
from  39  to  58  feet,  and  is  from  7  to  10  feet  below  mean  high  water 
in  the  harbor.  This  necessitated  the  establishing  of  an  elaborate 
system  of  drainage  over  the  entire  station  yard  area. 

To  accelerate  the  loading  and  unloading  of  trains,  high 
platforms  are  constructed  in  the  station  on  a  level  with  the 
floors  of  the  cars  in  order  to  avoid  the  use  of  car  steps  and  to 
increase  the  traffic  capacity  of  the  station.  Access  to  the 
street  is  gained  by  elevators  and  stairways.  There  are  twenty- 
one  standing  tracks  at  the  station  and  eleven  passenger  plat- 
forms providing  21,500  feet  of  platform  adjacent  to  passenger 
trains.  Within  the  station  area,  which  from  Tenth  Avenue  to 
the  normal  tunnel  sections  east  of  Seventh  Avenue  comprises 
28  acres,  there  is  a  total  of  about  sixteen  miles  of  track. 

The  service  plant  for  the  accommodation  of  machinery 
for  lighting,  heating  and  ventilating  the  station,  and  for  operat- 


THE   PENNSYLVANIA  RAILROAD   DEVELOPMENTS       41 

ing  the  interlocking  switch  and  signal  system,  is  located  in  an 
independent  building  south  of  the  station. 

The  power  house  to  supply  the  electrical  energy  for  the 
operation  of  the  tunnel  lines  and  the  Long  Island  Railroad 
is  located  in  Queens  Borough  on  property  adjoining  the  present 
Long  Island  station,  near  the  East  River.  As  at  present  designed 
the  dimensions  of  the  structure  are  200  by  262  feet  outside. 
It  accommodates  six  generating  units  of  5500  k.w.  (the  standard 
capacity  adopted  for  traction  work)  and  two  units  of  2500  k.w. 
for  lighting.  The  ultimate  capacity  of  this  station  when  fully- 
extended  will  be  about  105,000  k.w. 

The  East  River  division  begins  at  the  eastern  limits  of  the 
New^  York  station  in  Thirty-second  and  Thirty-third  streets, 
including  also  the  excavation  work  and  retaining  walls  for  the 
station  site  and  yard  to  the  track  level  westward  to  Ninth 
Avenue.  It  extends  eastward  from  the  station  through  tunnels, 
partly  three-track  and  partly  so-called  twin  tunnels  to  Second 
Avenue.  Thence  the  line  curves  to  the  left  under  private 
property  to  the  permanent  shafts  a  short  distance  east  of  First 
Avenue.  From  this  point  four  single-track,  cast  iron,  concrete- 
lined  tunnels  27^  feet  in  outside  diameter  cross  under  the  East 
River,  and  after  passing  through  permanent  shafts  near  the 
bulkhead  line  reach  the  surface  in  Long  Island  City  from  3000 
to  4200  feet  east  of  the  East  River.  The  eastern  portals  of  these 
tunnels  are  in  the  Sunnyside  yard.  The  total  length  of  this 
division  is  4.48  miles. 

The  total  length  of  the  entire  line  included  in  the  Pennsylvania 
extensions  into  New  York  City  is  13.66  miles.  There  are 
6.78  miles  of  single-track  tube  tunnels  and  the  average  length 
of  the  tunnels  between  portals  is  5.56  miles. 

In  all  parts  of  the  work  problems  were  encountered  requir- 
ing for  their  solution  large  expenditures  and  much  engineering 
skill;  but  many  of  the  difficulties  had  been  frequently  met  in 
previous  engineering  experience  and  the  methods  of  overcoming 
them  were  well  understood.  Thus  in  the  Meadows  division 
a  long  and  heavy  embankment  (part  of  which  was  on  submerged 
meadow  land)   and  many  bridge  foundations  had  to  be  con- 


42      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

structed.  In  the  Bergen  Hill  tunnels  a  very  tough  trap  rock 
was  encountered.  In  the  tunnels  under  New  York  City  the 
work  was  much  complicated  and  its  cost  greatly  increased  by 
the  necessity  of  caring  for  sewers,  water  and  gas  pipes,  and 
foundations  of  adjacent  buildings.  Many  troublesome  problems 
were  also  met  in  the  construction  of  the  tunnels  connecting  the 
East  River  with  the  Sunnyside  yard.  The  novel  features 
of  the  project,  however,  were  the  great  tunnels  carrying  the  line 
under  the  North  and  East  rivers. 

The  maximum  grade  west  of  the  terminal  station  occurs 
on  the  New  York  side  of  the  North  River.  It  is  2  per  cent 
in  the  west-bound  and  1.93  per  cent  in  the  east-bound 
tunnels.  The  ruHng  grades  for  the  ascending  traffic  are  1.32 
per  cent  in  the  west-bound  and  1.93  per  cent  in  the  east-bound 
tunnels.  In  the  tunnels  east  of  the  terminal  station  the  ruling 
grade  is  1.5  per  cent  for  both  east-bound  and  west-bound  traffic. 
These  grades  would  be  objectionable,  if  not  prohibitive,  with 
steam  locomotives  under  heavy  traffic,  but  the  development 
of  the  electric  locomotive  has  rendered  operation  over  these 
grades  entirely  practicable. 

From  the  junction  with  the  Pennsylvania  Railroad,  near 
Harrison,  N.  J.,  to  Woodside,  L.  I.,  a  distance  of  13.66  miles, 
there  is  an  average  of  1.5  curves  per  mile.  The  line  has  a  total 
curvature  of  230  degrees  and  the  maximum  curvature  is  2 
degrees. 

The  character  of  the  material  through  which  the  subaqueous 
tunnels  were  constructed  differed  greatly  in  the  two  rivers. 
The  bed  of  the  North  River  at  the  level  of  the  tunnels  consists 
of  silt,  composed  principally  of  clay,  sand  and  water.  The 
bed  of  the  East  River  at  the  working  point  is  made  up  of  a  great 
variety  of  materials,  including  quicksand,  sand,  boulders, 
gravel,  clay  and  bed-rock.  When  the  method  of  construction 
had  to  be  decided  upon  for  these  divisions  of  the  work  there 
were  no  thoroughly  satisfactory  precedents  to  follow  in  either 
case.  The  gas  tunnel  under  the  East  River,  the  partly  con- 
structed Hudson  tunnels  under  the  North  River,  the  St.  Clair 
tunnel  under  the  St.   Clair  River,  the  Blackwell  and  several 


THE   PENNSYLVANIA   RAILROAD   DEVELOPMENTS        43 

Other  tunnels  under  the  Thames  River  in  London,  suppHed 
much  useful  information. 

Most  of  the  methods  proposed  involved  temporary  struc- 
tures or  the  use  of  a  floating  plant  in  the  navigable  channels 
of  the  river.  After  full  consideration  of  the  subject,  however, 
it  was  decided  to  adopt  the  shield  method  with  compressed 
air  for  the  construction  of  the  sub-river  tunnels.  This  was  the 
only  method  recommended  by  the  chief  engineers  and  had  the 
great  advantage  of  conducting  all  operations  below  the  bottom 
of  the  river,  thus  avoiding  any  obstruction  of  the  channels. 

Experience  has  shown  that  it  is  much  more  difficult  to  con- 
struct tunnels  in  such  materials  as  were  encountered  in  the 
East  River  and  on  the  New  Jersey  side  of  the  North  River  than 
in  the  more  homogeneous  material  which  was  found  in  the 
greater  part  of  the  North  River  work.  During  the  progress 
of  construction  under  the  East  River  there  were  frequent  blow- 
outs through  fissures  opened  In  the  river  bed;  and  the  bottom 
of  the  river  over  the  tunnel  had  to  be  blanketed  continually 
with  clay  to  check  the  flow  of  the  escaping  air  from  the  shield. 

In  view  of  the  serious  difficulties  which  is  was  thought  might 
be  encountered  in  the  apphcation  of  the  shield  method  to  the 
East  River  work,  several  other  methods  for  the  execution  of 
this  division  received  special  consideration.  One  of  these  was 
the  freezing  process,  and  an  extended  experiment  was  made 
to  prove  its  possibilities.  A  pilot  tunnel  y^  feet  in  diameter 
was  driven  into  the  bed  of  the  East  River  for  a  distance  of  i6o 
feet.  Circulating  pipes  w^ere  established  in  it  and  brine,  at  a 
very  low  temperature,  was  passed  through  them  until  the  ground 
was  frozen  for  a  distance  of  about  15  feet  around  the  tunnel. 
Observations  were  carefully  made  to  determine  the  rate  of 
cooling  and  other  important  points  connected  with  the  process. 
It  was  found,  however,  that  the  construction  of  the  tunnels 
was  progressing  satisfactorily  by  the  shield  method;  and  as  so 
much  time  was  required  to  freeze  the  material  as  to  make  the 
freezing  process  of  no  advantage  in  this  particular  case,  the 
experiment  was  discontinued. 

The  sub-river  tunnels  consisted  of  a  cast  iron  shell  of  seg- 


44       SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

mental  bolted  type  with  an  outside  diameter  of  23  feet  and  lined 
with  concrete  having  a  normal  thickness  of  2  feet  from  the  out- 
side of  the  shell.  Through  each  plate  of  the  shell  there  is  a 
small  hole,  closed  with  a  screw  plug,  through  which  grout  may 
be  forced  into  the  surrounding  material.  Each  tunnel  contains 
a  single  track. 

A  concrete  bench,  the  upper  surface  of  which  is  i  foot  below 
the  axis  of  the  tunnel,  is  built  on  each  side  of  the  track,  the 
distance  between  the  bench  faces  being  1 1  feet  8  inches.  Within 
these  benches  are  ducts  carrying  the  electric  cables.  The 
principal  object  in  adopting  single-track  tunnels  instead  of  a 
larger  two-track  section  was  to  avoid  the  danger  of  accidents 
due  to  the  obstruction  of  both  tracks  by  derailment  or  otherwise. 

The  tunnels  are  just  large  enough  to  allow  the  passage  of 
the  train  with  perfect  safety,  for  it  was  believed  that  with 
such  an  arrangement  the  motion  of  the  trains  would  secure  a 
thorough  ventilation.  Experience  seems  to  justify  this  assump- 
tion; but  in  order  to  insure  thorough  ventilation  under  unusual 
conditions,  such  as  the  stoppage  of  trains  in  the  tunnels,  a  com- 
plete ventilation  plant  is  provided  for  each  tube.  Furthermore 
the  rapidity  and  safety  of  construction  were  increased  by  making 
the  tunnels  as  small  as  possible;  since  one  of  the  difficulties  in 
the  shield  method  of  tunnei  driving  is  the  difference  in  hydro- 
static pressure  between  the  top  and  bottom  of  the  shield,  which 
increases  with  the  diameter  of  the  tunnel. 

The  concrete  lining  was  introduced  to  insure  the  permanency 
of  the  structure,  to  strengthen  it  from  outward  pressure  and  to 
guard  it  against  injury  from  accidents  which  might  occur  in 
the  tunnel.  At  points  where  unusual  stresses  were  anticipated, 
as  where  the  tubes  pass  from  rock  into  soft  ground,  the  shell  is 
composed  of  steel  instead  of  cast  iron  plates.  One  of  the  most 
important  questions  connected  with  the  design  of  these  tunnels 
was  their  probable  stability  under  long,  continued  action  of 
heavy  and  rapid  railroad  traffic.  The  tunnels  are  lighter  than 
the  materials  which  they  displace  when  the  weight  of  the  heavy, 
live  load  is  included. 

Some  idea  of  the  increase  in  passenger  traffic  resulting  from 


THE   PEXXSYLVANIA  KAILROAD   DEVELOPMENTS        45 

the  establishment  of  the  tunnel  Hne  may  be  obtained  by  com- 
paring the  proposed  daily  train  movement  from  the  new  ter- 
minal station  with  the  train  movement  at  other  important  rail- 
road stations  as  given  below. 

Total  trains       Movement 
in  and  out      at  maximum 
for  24  hours.  hour. 

Jersey  City 281  29 

Broad  Street,  Philadelphia 538  48 

Union  Station,  St.  Louis 462  89 

South  Terminal  Station,  Boston 861  87 

Grand  Central,  New  York 357  44 

Pennsylvania  Station,  New  York 500  50 

From  Proceedings  Am.  Soc.  C.E.,  Sept.,  1909.  "  The  New  York.  Tunnel  Exten- 
sion of  the  Penn.  R.  R.,"  by  Chas.  W.  Raymond,  M.  .\m.  Soc.  C.  E. 


CHAPTER  VIII 

BERGEN  HILL  TUNNELS  OF  THE  PENNSYLVANIA  RAILROAD 

These  two  single-track,  parallel  tunnels,  each  5920  feet 
in  length,  are  on  the  west  shore  of  the  Hudson  River,  and  pene- 
trate Bergen  Hill,  which  is  a  dyke  of  trap  rock  forming  a  southern 
extension  of  the  Hudson  River  Palisades.  The  contractors 
on  this  work  were  the  John  Shields  Construction  Company 
and  William  Bradley.  The  work  was  contracted  for  January 
20,  1906,  and  was  completed  December  31,  1908. 

Starting  west  from  the  Weehawken  shaft  the  tunnels  passed 
through  a  fault  for  a  distance  of  400  feet.  The  broken  ground 
in  this  fault  consists  of  decomposed,  sandstone,  shale,  feldspar, 
calcite,  etc.,  interspersed  with  masses  of  harder  sandstone  and 
baked  shale,  gradually  merging  into  a  compact  granular  sand- 
stone. The  trap  rock  is  encountered  about  940  feet  from  the 
shaft.  The  full  face  of  the  tunnel  is  in  trap  rock  at  about  1000 
feet  from  the  shaft  and  continues  in  this  formation  to  the 
western  portal.  Sandstone  and  trap  rock  are  of  the  Triassic 
period,  the  latter  being  classified  as  diabase.  The  character  of 
the  trap  rock  varied.  In  places  a  very  hard,  fine-grained  trap, 
almost  black,  was  found,  having  a  specific  gravity  of  2.98  and 
weighing  186  pounds  per  cubic  foot.  In  this  rock  the  average 
time  required  to  drill  a  lo-foot  hole  with  a  No.  34  "  Slugger  " 
drill  under  90  pounds  pressure  was  10  hours.  The  remainder 
of  the  trap  varied  from  this  extremely  hard  quahty,  due  to 
different  amounts  of  quartz  and  feldspar,  down  to  a  coarse- 
grained rock  resembling  a  light  colored  granite  and  quite  hard. 

The  speed  of  drilhng  the  normal  trap  in  the  heading  was 
approximately  20  to  25  minutes  per  foot  as  compared  to  60 
minutes  per  foot  as  noted  above  in  the  harder  rock.  The 
larger  amounts  of  feldspar  and  quartz  gave  a  greater  brittle- 

46 


SECTION  NO.  12 
19  6    SPAN  TWIN  TUNNELS 


ON  NO.  4 
WIN  TUNNELS 


General 


NOTE;-  The  Sub-divisions  of  cncli  Cross-section  are  numljered  in  order  as  excavated 


W££HAWKEN  RIVER  TUNNELS 


SINGLE  E 

General  Method  of  Excavation  Adopted  in  the  Bergen  Hill  Tunnelsof  the  Pennsylvania  R.R.,  entering  New  York. 


BERGEN  HILL  TUNNELS 


47 


ness  in  the  latter  case,  and  made  easier  drilling.  The  normal 
trap  has  a  specific  gravity  of  from  2.85  to  3.04  and  weighs  from 
179  to  190  pounds  per  cubic  foot. 

These  tunnels  were  excavated  entirely  by  the  center  top 
heading  method,  which  has  found  almost  universal  application 
in  the  United  States.     The  drills  used  throughout  the  work 


Rock  Packing 


SKETCH  SHOWING  DIVISION  OF  LINING, 
FOR  PURPOSES  OF  CONSTRUCTION,  AND  NAMES  OF  SECTIONS 

Typical  Cross-section  of  P.R.R.  Bergen  Hill  Tunnels 

were  No.  34  Rand  ''  Sluggers  "  with  a  3 f -inch  cylinder  diameter. 
The  steel  used  was  "  Black  Diamond,"  if-inch  octagon  section. 
These  were  from  2  to  12  feet  in  length.  The  bits  started  with 
a  diameter  of  2f  to  3  inches,  which  was  held  to  a  depth  of 
about  6  feet,  when  it  was  gradually  decreased  to  from  i|  to  2^ 
inches  at  the  bottom  of  a  12-foot  hole.  There  was  an  average 
of  one  sharpening  for  each  foot  drilled  and  about  one-quarter 


48      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

of  an  inch  of  steel  was  used  for  each  sharpening.  The  quantity 
of  steel  used,  lost  or  scrapped,  was  one  foot  for  every  lo 
cubic  yards  of  rock  excavated,  equivalent  to  1.2  inches  per 
cubic  yard.  An  "  Ajax  "  drill  sharpener  was  used  and  proved 
very  satisfactory. 

On  the  bench  rubber  and  cotton  hose  covered  with  woven 
marline,  3  inches  in  inside  diameter,  was  used  in  50-foot  lengths. 
For  the  drills  the  same  style  of  hose  was  used,  one  inch  in  diameter 
and  in  25-foot  lengths;  and  for  the  steam  shovels  2^-inch  hose 
was  used  in  50-foot  lengths.  Hose  coverings  of  wound  marline 
and  of  woven  marline  with  spiral  steel  wire  covering  were 
tried.  But  they  were  not  satisfactory  owing  to  the  unwinding 
of  the  marline  and  to  the  bending  of  the  steel  covering. 

The  average  quantity  of  powder  used  was  2.9  pounds  per 
cubic  yard.  Both  40  and  60  per  cent  dynamite  were  used, 
the  latter  being  exclusively  employed  in  the  latter  part  of  the 
work.  The  rock  broke  well.  In  sandstone  the  weight  of  pow- 
der used  per  cubic  yard  was  much  greater  than  in  trap. 

In  drilling  the  central  shaft  a  6-hole  cut  was  made  on  the 
center  line,  later  enlarged  by  making  18  holes  to  a  depth  of 
6  feet.  In  a  24-hour  day  the  average  advance  was  4  feet.  In 
the  shaft  the  drills  were  run  by  steam  until  a  depth  of  150  feet 
had  been  reached,  when  compressed  air  became  available.  Four 
drills  were  used  until  compressed  air  was  adopted,  after  which 
six  were  operated. 

The  drills  were  at  work  5.2  hours  per  8-hour  shift.  They 
were  actually  "  hitting  the  rock  "  2.5  hours  per  shift.  The 
average  depth  drilled  per  hour  during  the  time  of  5.2  hours 
was  2.66  feet.  The  average  footage  drilled  per  hour,  all  delays 
included,  was  1.64  feet.  The  following  figures  give  the  estimated 
cost  per  drill  per  day: 

Drill  runner,  i  at  $3.50  per  day $3-5o 

Helper,  i  at  $2.00  per  day 2.00 

Nipper,  1/5  at  $1.75  per  day 0.35 

Heading  foreman,  1/12  at  $5.00 0.42 

Walking  boss,  1/50  at  $7.50  per  day 0.15 

Blacksmith,  1/12  at  $4.00  per  day 0.34 


BEKGEX   HILL  TUNNELS  49 

Blacksmith's  helper,  1/12  at  $2.00  per  day 0.16 

Machinist,  1/12  at  $3.00  per  day 0.25 

Machinist's  helper,  1/24  at  $1.75  per  day 0.07 

Pipe  fitter  and  helper,  1/50  at  $5.00  per  day o.io 

Oil,  waste,  smith  coal,  etc 0.24 

Drill  steel,  6  inches  per  shift 0.24 

Cost  per  shift $7.78 

The  average  footage  drilled  per  cubic  yard  was  5  feet ;  the  num- 
ber of  feet  drilled  per  drill  per  shift  was  10.5  to  12;  the  number 
of  yards  excavated  per  drill  per  shift  was  3.5;  the  cost  of 
drilling  per  yard  was  $2.22.  In  the  foregoing  the  quantities 
paid  for  have  been  the  basis  of  estimate;  the  quantities  taken 
out  were  10  per  cent  more  than  paid  for. 

The  following  table  gives  a  comparative  record  of  the  Bergen 
Hill  tunnels  and  the  Simplon  tunnel.  The  formation  in  the 
Italian  end  of  the  Simplon  was  an  antigoric  gneiss,  a  very  hard 
rock. 

Bergen  Hill  Simplon 

Drill  set  up  in  heading,  percentage  total 

elapsed  time 50%  60% 

Actually   drilling    the   rock,  percentage  of 

total  elapsed  time 50%  50%  • 

Average  advance  per  round  (attack) 8.5  ft.  3.8  ft. 

Average  time  for  each  attack 36  hrs.  5  hrs. 

Average  advance  per  day  of  24  hours  ....  5  ft.  18  ft. 

Depth  of  holes 10  ft.  4.6  ft. 

Diameter  of  holes 2f  ins.  2j  ins. 

Lineal  feet  drilled  per  hour,  per  drill 2.7  7 

Lineal  feet  drilled  per  cubic  yard 5  6 

Pounds  of  dynamite  per  cubic  yard 3.4  to  5.7         SI 

Average  depth  drilled  with  one  sharpening.  12  ins.  6h  ins. 

Note.     From  paper  by  W.  F.  Lavis,  before  the  American  Society  of  Civil 
Engineers,  April  6,  1910. 

The  conditions  affecting  the  disposal  of  the  muck  after 
blasting  were  not  the  same  at  the  two  ends  of  the  Bergen  Hill 


50      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

tunnels.  On  the  eastern  end  the  grade  descended  toward 
Weehawken,  and  at  the  western  end  there  was  an  ascending 
grade.  At  Weehawken  the  mouth  of  the  tunnels  was  at  the 
bottom  of  a  shaft  80  feet  deep.  The  muck  in  the  tunnel  cars 
was  hoisted  by  elevators  to  a  platform  at  the  top,  from  which 
it  was  dumped  into  standard  gage  cars  and  later  hauled  to  the 
crusher  or  storage  pile,  some  500  feet  distant.  At  the  western 
end  the  cars  were  hauled  directly  to  the  surface  through  the 
approach  cut;  and  the  material,  except  that  which  was  required 
for  concrete  and  rock  packing,  was  hauled  from  1000  to  3000 
feet  across  the  Hackensack  Meadows.  The  disposal  tracks 
were  of  36-inch  gage  and  were  generally  laid  with  60-pound 
rails. 

Except  for  about  1000  feet  in  each  tunnel  at  the  Weehawken 
end,  where  the  muck  was  loaded  by  hand,  four  steam  shovels 
operated  by  compressed  air  were  used,  one  in  each  working 
face.  Three  30-ton  "  Vulcan  "  and  one  38-ton  "  Marion  " 
shovels  were  used.  These  were  on  a  standard  gage  track,  and 
during  blasting  operations  were  moved  300  to  500  feet  back 
from  the  face.  At  Weehawken  empty  cars  of  an  average  load 
capacity  of  one  cubic  yard  were  pushed  to  the  shovels  by  hand 
from  the  storage  tracks.  When  loaded  they  were  started  down 
grade  by  the  bucket  and  coasted  to  the  storage  track  near 
the  shaft.  The  unloaded  cars  were  hauled  back  to  the  storage 
track  by  mules,  one  mule  handling  two  cars.  When  the  tunnels 
were  in  full  working  order  sixty  muck  cars  were  in  use,  about 
evenly  divided  between  the  two  tunnels. 

When  mucking  by  hand  the  mucking  gangs  consisted  of 
from  15  to  20  men.  The  maximum  output  per  shift  was  50 
cubic  yards  and  the  average  35  cubic  yards.  The  maximum 
output  of  any  of  the  shovels  was  159  cubic  yards  per  shift  and 
the  best  average  in  any  one  month  was  60  cubic  yards  per  shift. 
As  the  shovels  were  generally  idle  for  one  shift  out  of  three, 
the  quantity  actually  handled  averaged  90  cubic  yards  per  shift 
during  the  shifts  that  the  shovels  were  at  work.  These  quan- 
tities are  "  place  measurement  "  and  equal  to  about  twice  ''car 
measurement."     The  shovels  at  both  ends  were  usually  worked 


CONDUCTOR  POCKET 

Typical  Dimensioned  Cross-Sections,  Bergen  Hill  Tunnels  of  the  Pennsylvania  R.R. 


BERGEN   HILL  TUNNELS  51 

with  day  crews — one  night   crew  worked  the  shovels  in  either 
tunnel  as  occasion  required. 

At  the  Hackensack  or  western  end  one-way  dump  cars  were 
used  having  a  capacity  of  four  cubic  yards.  These  were  hauled 
by  dinky  locomotives,  of  which  there  were  three,  and  later  four, 
in  use.  To  haul  the  cars  outside  to  the  dumps  and  crusher 
one  15-ton,  10  by  16-inch,  Porter  locomotive  was  used.  In  the 
tunnels  three  12-ton,  9  by  14-inch,  Vulcan  locomotives  were 
used.  About  thirty  Allison  dump  cars  were  on  the  job,  of 
which  there  were  generally  three  to  six  undergoing  repairs. 
The  work  was  usually  arranged  so  that  the  heavy  mucking 
shifts  alternated  in  the  two  tunnels.  Two  engines  were  then 
worked  in  the  one  tunnel  and  a  single  engine  in  the  other  tunnel. 
Generally  four  cars  were  hauled  out  together. 

The  muck  from  the  central  shaft  headings  was  loaded  by 
hand  into  cars,  which  were  then  taken  to  a  platform  20  feet 
above  the  surface  by  a  double  elevator  and  dumped  into  storage 
bins  or  wagons. 

The  method  by  which  the  best  results  were  obtained  was 
as  follows:  A  full  round  was  blasted  every  thirty-six  hours, 
securing  an  advance  of  9  feet  of  full  tunnel  section.  During 
the  first  shift  of  three,  when  the  blasting  had  been  completed 
and  the  lights  strung,  the  shovel  moved  forward,  cleaning  the 
floor  to  the  main  pile  of  muck.  The  material  from  the  blast 
was  scattered  from  1 50  to  300  feet  back  from  the  face.  During 
this  shift  also  ,the  drillers  mucked  the  heading  and  set  up  the 
drills,  the  muckers  helping  to  carry  the  drills  and  their  columns. 
During  the  second  shift  the  main  pile  of  muck  was  disposed  of, 
leaving  not  more  than  two  or  three  hours'  work  for  the  shovel 
on  the  third  shift.  This  left  nearly  the  whole  of  the  third 
shift  for  drilling  the  lift  holes. 

At  Weehawken  difficulty  was  encountered  from  the  fog 
and  smoke  in  the  tunnels  after  blasting.  This  was  aggravated 
on  days  when  the  barometric  pressure  outside  was  low.  A 
6-foot  fan,  driven  by  an  electric  motor,  was  installed  in  the 
cross-passage  900  feet  from  the  shaft  (the  heading  being  at 
that  time  about  300  feet  in  advance  of  this  point)  to  force  the 


52      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

air  from  the  south  into  the  north  tunnel,  drawing  it  in  at  the 
mouth  of  the  south  tunnel  and  discharging  it  at  the  mouth  of 
the  north  tunnel,  thus  insuring  a  circulation  in  both  tunnels. 
The  fan  was  moved  ahead  to  the  next  cross-passage  when  the 
work  had  progressed  far  enough.  The  compressed  air  dis- 
charged from  the  drills  kept  the  headings,  as  well  as  that  part 
of  the  tunnel  between  the  headings  and  the  fan,  fairly 
clear. 


^  ^ ^,-  *     ' '  *     North  • Weehawken 

I  ~37^rzr~'^i~t!u  ^_zm;. 


Shaft 


le!"^— '■-;;;,/;■'. '  ^rr-T~:~'-~r:3J^^^^^^^^^^^^^^^^^ 

Method  of  Ventilation,  Bergen  Hill  Tunnels. 

The  total  elapsed  time  from  starting  at  the  Weehawken 
end  to  the  completion  of  the  excavation  was  almost  exactly 
three  years.  The  total  number  of  days  actually  worked  was 
940,  giving  an  average  progress  of  6.26  feet  per  working  day  at 
each  of  the  two  tunnels.  Omitting  the  central  shaft  headings 
this  gives  an  average  rate  of  progress  for  each  working  face  of 
3.13  feet  per  day.  At  the  Weehawken  end  the  total  number 
of  days  worked  was  763,  divided  as  follows:  In  timbered 
section,  186  days  and  about  426  feet,  giving  an  average  rate 
of  2.3  feet  per  day  in  each  tunnel;  in  hard  sandstone,  176  days 
and  about  563  feet,  at  an  average  rate  of  3.2  feet  per  day  in  each 
tunnel;  in  hard  trap  rock,  112  days  and  about  267  feet,  giving 
an  average  rate  of  2.4  feet  per  day  in  each  tunnel;  in  ordinary 
trap  rock,  289  days  and  about  13 16  feet,  the  average  rate  being 
4.55  feet  per  day  in  each  tunnel. 

The  best  month's  work  was  in  the  Hackensack  end,  in 
trap  rock,  and  was  as  follows:  May,  1907,  working  in  the 
south  tunnel  from  the  portal  to  the  central  shaft  headings, 
139  lineal  feet,  equivalent  to  about  5  feet  of  heading  per  day; 
November,  1907,  enlargement  of  headings,  176  lineal  feet, 
equivalent  to  6  feet  per  day;  April,  1908,  working  from  the  cen- 


BERGEN   HILL  TUNNELS  53 

tral  shaft  headings  to  the  Weehawken  headings  in  the  north 
tunnel,  145  lineal  feet  or  5.2  feet  per  day. 

In  the  central  shaft  headings  during  April,  1907,  122  feet 
of  lineal  heading,  averaging  3.8  cubic  yards  per  lineal  foot, 
were  taken  out  in  the  south  tunnel.  This  is  equal  to  5  feet 
per  day  for  the  24  days  worked. 

The  best  week's  work  at  either  of  the  main  working  faces, 
when  the  full  section  was  being  excavated  in  trap  rock,  was 
803  cubic  yards,  equal  to  41.8  lineal  feet  of  full  section  tunnel, 
or  an  average  of  6  lineal  feet  of  full  section  per  day. 

The  largest  number  of  cubic  yards  taken  out  in  any  one  week 
from  one  working  face  was  1087,  equal  to  about  56.6  lineal 
feet  of  full  section  or  an  average  of  8.1  lineal  feet  of  full  section 
per  day. 

The  largest  yardage  for  the  whole  work  in  any  one  week 
was  3238  cubic  yards  from  four  working  faces — two  faces  at  the 
Weehawken  end  in  full  section  and  two  faces  at  the  Hackensack 
bench  and  enlargement.  This  was  equivalent  to  168.4  lineal 
feet  of  full  section  tunnel  or  an  average  of  6  lineal  feet  per  day 
from  each  working  face. 

The  plant  first  installed  at  Weehawken  and  taken  over 
by  the  contractor  who  finished  the  work  was  composed  very 
largely  of  second-hand  material.  Eventually  most  of  it  had 
to  be  replaced.  Insufficient  and  inefficient  plant,  and  delay 
in  installation,  were  largely  responsible  for  the  small  progress 
made  at  the  beginning  of  the  work.  An  endeavor  to  continue 
the  use  of  this  plant  not  only  caused  added  delay,  but  also 
involved  a  large  expense.  The  plant  installed  by  the  original 
contractor  proved  inadequate  to  supply  the  air  for  the  shovels 
and  drills.  The  latter  equipment  consisted  of  two  shovels 
requiring  iioo  cubic  feet  per  minute  and  20  Rand  "  Slugger  " 
drills  using  2088  cubic  feet  of  free  air  per  minute.  An  arrange- 
ment was  made  with  the  O'Rourke  Construction  Company, 
then  at  work  on  the  sub-river  tunnels,  to  provide  4000  cubic 
feet  of  free  air  per  minute  at  100  pounds;  and  the  old  plant 
was  shut  down.  The  air  compressing  plant  which  finally  sup- 
plied the  air  for  the  Bergen  Hill  tunnels  was  built  by  the  Ingersoll- 


54      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

Rand  Company.  The  air  was  compressed  to  40  pounds  by 
low  pressure  machines,  one  being  used  all  the  time  and  two 
when  necessary.  These  compressors  were  of  the  Corliss  steam 
driven  duplex  type,  with  cross-compound  steam  cylinders  and 
simple  duplex  air  cyhnders.  Each  unit  had  a  capacity  of  nearly 
4000  cubic  feet  of  free  air  per  minute.  This  air  at  40  pounds 
was  delivered  to  an  Ingersoll-Rand  high  pressure  machine  of 
the  same  general  type,  having  cross-compound  Corliss  steam 
cylinders  14  and  26  by  36  inches,  with  piston  inlet  air  cylinders 
13  J  inches  in  diameter.  This  machine  compressed  to  100  pounds. 
The  capacity  of  this  high  pressure  machine  taking  air  at  atmos- 
pheric pressure  was  920  cubic  feet  per  minute  at  85  r.p.m. 
Taking  air  at  40  pounds  from  the  low  pressure  machines,  and 
working  at  a  somewhat  higher  speed,  this  compressor  alone 
supplied  all  the  air  used  at  the  Weehawken  end  (approximately 
4000  cubic  feet  per  minute)  from  December,  1906,  to  November, 
1907.  With  very  few  exceptions  the  pressure  was  steadily 
maintained  at  from  90  to  100  pounds  and  there  was  no  break- 
down of  any  kind. 

At  the  Hackensack  end  the  old  plant  was  also  found 
inadequate  and  a  new  installation  was  made  in  another  situa- 
tion, as  it  was  found  that  the  old  site  in  the  meadows  was  on 
soft  ground  and  the  vibration  of  passing  trains  caused  the 
settling  of  foundations  and  the  breaking  of  steam  pipes.  The 
new  plant  included  two  pairs  of  Stirling  boilers  with  a  total 
capacity  of  2000  h.p.  Eight  compressors  were  installed,  all  of 
the  Ingersoll-Rand  straight-Hne  steam  driven  type,  24  and  24 
by  30  inches,  each  with  a  rated  capacity  of  1250  cubic  feet  of 
free  air  per  minute.  Seven  of  these  were  generally  worked  to  the 
limit  of  their  capacity  to  supply  the  necessary  air. 

The  maximum  requirements  of  air  at  the  Hackensack  or 
western  end  were  originally  estimated  as  follows : 

Central  shaft,  four  headings 24  drills 

Hackensack  end,  two  working  faces 20  drills 

44  drills 


BERGEN    HILL  TUNNELS  55 

Cu.  Ft.  Free 
Air  per  Min. 

44  Slugger  drills 4,350 

2  steam  shovels 1,600 

Pumps  and  machine  shops  (estimated) ....  i  ,000 

4  hoisting  engines,  placing  concrete 2,000 

4  derricks 2,000 

Total iO'95o 

The  rated  total  capacity  of  the  eight  compressors  was  10,000 
cubic  feet  of  free  air  per  minute.  It  was  considered  that  not 
more  than  two-thirds  of  the  machine  equipment  would  be  work- 
ing at  the  same  time.  The  actual  air  requirement,  therefore, 
was  estimated  to  be  about  8000  cubic  feet  of  free  air  per  minute, 
leaving  a  margin  of  one  spare  compressor  for  emergencies. 
The  heaviest  actual  requirement,  therefore,  was  approximately 
as  follows: 

Cu.  Ft.  Free 
Air  per  Min. 

40  drills 3828 

2  shovels 1600 

Pumps  and  machine  shop  (estimated) 1000 

2  derricks 1000 

Total 7428 

After  November,  1907,  when  the  enlargement  of  the  central 
shaft  heading  had  been  completed,  the  air  requirements  fell 
off  to  the  following  figures: 

Cu.  Ft.  Free 
Air  per  Min. 

32  drills 2958 

2  shovels 1600 

Pumps,  etc 1000 

3  hoisting  engines  on  concrete,  each  working 

one-third  time 500 

2  derricks 1000 

Total 7058 


56      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

The  average  number  of  drills  per  shift  was  about  25  at  the 
two  working  faces.  There  were  also  5  to  10  drills  used  for 
trimming  and  cleaning  up  for  concrete,  with  say  an  average 
of  7.     This  made  a  total  of  32  drills  in  operation. 

In  lining  and  otherwise  completing  the  interior  of  the  tunnels 
the  following  quantities  of  the  various  materials  were  used, 
the  figures  being  given  per  lineal  foot  of  completed  tunnel: 

Concrete 7.64  cu.yd. 

Rock  packing 3.22  cu.yd. 

Paid  for 1.48  cu.yd. 

Outside  standard  section 1.74  cu.yd. 

Iron  and  steel 44.2  lbs. 

Vitrified  conduits 84.0  duct  ft. 

Water  proofing 13.0  sq.ft. 

Flags 3.3  sq.ft. 

The  quantities  of  some  of  the  main  items  of  materials  in  the 
Bergen  Hill  tunnels  are  as  follows: 

Excavation 263,000  cu.yd. 

Cement  used  (concrete  and  grout) .  .     95,000  bbls. 

Concrete 95,ooo  cu.yd. 

Dynamite  for  blasting 600,000  lbs. 

Structural  steel 50,000  lbs. 

The  foregoing  figures  are  taken  from  a  paper  by  Mr.  W.  F.  Lavis,  M.  Am. 
Soc.  C.E.,  on  the  New  York  Tunnel  Extension  of  the  Pennsylvania  Railroad 
Bergen  Hill  Tunnels  in  the  Proceedings  of  the  American  Society  of  Civil 
Engineers  for  February,  19 10. 


CHAPTER  IX 
NORTH  RIVER  TUNNELS  OF  THE  PENNSYLVANIA  RAILROAD 

The  section  described  in  this  chapter  is  that  lying  between 
Tenth  Avenue,  New  York,  and  the  large  shaft  built  by  the 
Pennsylvania  Railroad  Company  at  Weehawken,  N.  J.  It 
thus  comprises  the  tunnels  passing  under  the  North  or  Hudson 
Rivers.  The  O'Rourke  Engineering  and  Construction  Com- 
pany were  the  contractors.  The  subject  will  be  treated  in  the 
following  order,  viz.,  shafts,  plant  and  river  tunnels. 

Two  shafts  were  provided,  one  on  the  New  York  side  and 
one  on  the  New  Jersey  side.  They  were  placed  as  near  as  possible 
to  the  point  at  which  the  disappearance  of  the  rock  from  the 
tunnels  made  it  necessary  to  start  the  portion  of  the  work  which 
must  be  driven  by  shields. 

The  Manhattan  shaft  was  located  about  loo  feet  north  of 
the  tunnel  center  and  there  is  nothing  out  of  the  ordinary  about 
its  construction.  It  was  55  feet  deep,  with  a  cross-section  of 
32  by  22  feet.  The  amount  of  excavation  involved,  including 
drifts,  was  2010  cubic  yards.  The  shaft  was  Hned  with  concrete 
reinforced  with  steel  beams  down  to  solid  rock,  the  amount 
of  concrete  used  being  209  cubic  yards.  The  cost  of  the  shaft 
was  ^T,\  cents  per  cubic  foot.  The  first  13  feet  of  depth  was 
in  filled,  or  made,  ground,  and  below  that  the  materials  encoun- 
tered were  red  mica  schist  and  granite.  The  total  cost  to  the 
company  was  $12,943. 

The  Weehawken  shaft  was  a  comparatively  large  piece  of 
work.  Its  depth  was  76  feet  and  its  dimensions  at  the  top 
were  100  by  154  feet,  reducing  to  56  by  116  feet  at  the  bottom. 
The  total  amount  of  excavation  was  55,315  cubic  yards,  com- 
posed of  sand  and  decomposed  trap  and  sand  rock.  The  cost 
of  excavation  per  cubic  foot  was  33.7  cents.     The  shaft  was 

57 


58      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

lined  with  9810  cubic  yards  of  concrete  with  steel  tie-rods  in 
the  rock.  This  shaft  was  started  June  11,  1903,  and  completed 
September  i,  1904,  at  a  total  cost  to  the  railroad  of  $166,163. 
It  was  located  over  the  tunnels  and  included  both  of  them. 
All  work  was  carried  on  from  these  two  shafts. 

The  installation  of  the  power  plant  on  the  Manhattan 
side  occupied  the  time  from  May,  1904,  to  April,  1905.  Air 
pressure  was  on  the  tunnels  on  the  New  York  side  on  June  25, 
T005,  and  on  the  Weehawken  side  on  the  29th  of  the  same  month. 
While  the  plants  in  both  cases  were  almost  identical  local  con- 
ditions necessitated  some  changes  in  arrangement. 

The  main  items  and  the  cost  of  the  separate  items  in  one 
power  house  are  as  follows: 

3  500  h.p.  Stirling  water  tube  boilers $15,186 

2  Blake  feed  pumps 740 

1  Worthington  surface  condenser 6,539 

2  General  Electric  circulating  pumps,  electric.  5,961 

3  low  pressure  compressors,  Ingersoll-Rand .  .  .  33,780 

1  high  pressure  compressor,  Ingersoll-Rand .  .  .       6,665 
3  Blake  hydrauHc  power  pumps 3,o75 

2  General  Electric  electric  generators  and  en- 

gines         7,626 

Total $79,572 

The  following  gives  a  summary  of  the  total  cost  of  one  plant : 

Total  cost  of  main  items  of  plant $  79,572 

Cost  of  four  shields,  appurtenances  and  dem- 
olition (including  repairs) 105,560 

Cost  of  piping  to  drills,  derricks  and  miscel- 
laneous plant 101,818 

Cost  of  installation,  including  preparation  of 
site 39,534 

Total  prime  cost  of  one  power  house  plant .  .   $324,484 

At  each  shaft  there  were  three  Class  "  F  "  Stirling  boilers 
rated  at  500  h.p.     Each  boiler  had  5000  square  feet  of  heating 


NORTH  RIVER  TUNNELS  59 

surface  and  ii6  square  feet  of  grate  area,  with  independent 
smoke  stacks,  54  inches  in  diameter  and  100  feet  in  height  above 
grate  level.  Shaking  grates  were  used  and  firing  was  done 
by  hand.  There  were  four  doors  to  each  furnace.  An  average 
of  20  tons  of  buckwheat  coal  was  used  in  24  hours,  at  each 
plant.     The  average  steam  pressure  carried  was  135  pounds. 

There  were  two  feed  pumps  at  each  plant  having  a  free 
discharge  capacity  of  700  cubic  feet  per  minute,  the  size  being 
10  and  6  by  10  inches. 

At  each  plant  there  were  three  Ingersoll-Rand  low  pressure 
compressors  used  to  supply  air  to  the  working  chambers  of 
the  subaqueous  shield-driven  tunnels.  They  were  also  used 
on  occasion  to  supply  air  to  the  high  pressure  compressors 
when  the  latter  were  hard  pressed  by  an  unusual  demand  for 
increased  high  pressure  air.  These  machines  were  of  a  new 
design,  of  duplex  Corliss  type  with  cross-compound  steam 
cylinders,  designed  to  work  condensing  but  capable  of  operating 
non-condensing.  The  air  cylinders  were  single  stage  duplex. 
Steam  cyhnders  were  14  and  30  inches  in  idiameter  by  36  inches 
stroke.  Air  cylinders  were  23  2  inches  in  diameter  and  had  a 
combined  capacity  of  35.1  cubic  feet  of  free  air  per  revolution. 
While  the  machines  were  capable  of  running  at  135  r.p.m., 
their  normal  speed  was  about  125  r.p.m.,  at  which  the  free  air 
capacity  was  4389  cubic  feet  per  minute  or  263,340  cubic  feet 
per  hour.  The  steam  pressure  was  135  pounds  and  an  air 
pressure  of  50  pounds  could  be  obtained  from  each  compressor. 

One  high  pressure  Ingersoll-Rand  compressor  of  cross- 
compound  Corliss  steam  driven  type  was  located  in  each  of  the 
plants.  The  capacity  was  about  iioo  cubic  feet  of  free  air  per 
minute  when  running  at  85  revolutions  and  using  atmopsheric 
air  for  the  intake.  When  taking  air  at  30  pounds  from  the  low 
pressure  compressors  the  capacity  was  3305  cubic  feet  per  minute 
per  machine.  With  a  low  pressure  compressor  running  at  125 
r.p.m.  it  furnished  enough  air  at  30  pounds  to  supply  the  high 
pressure  compressor  running  at  85  r.p.m.  With  a  high  pressure 
machine  delivering  at  150  pounds  the  combined  capacity  of 
this  arrangement  was  4389  cubic  feet  of  free  air  per  minute. 


60 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


The  air  was  delivered  into  a  receiver  4  feet  6  inches  in  diameter 
by  12  feet  high. 

There  were  two  Worthington  surface  condensers  at  each 
plant,  each  with  coohng  surface  sufficient  to  condense  22,500 
pounds  of  steam  per  hour,  with  water  at  30  degrees  Fahrenheit, 
maintaining  a  vacuum  of  26  inches  with  the  barometer  at  30 
inches.      Each  condenser  was  fitted  with  a   horizontal  direct 


Interior  of  Weehawken   Air   Compressor  Plant   for  P.R.R.   North    River 

Tunnels. 


acting  vacuum  pump.  Two  8-inch  centrifugal  circulating 
pumps  driven  by  36  h.p.  direct  current  motors,  running  at  220 
volts  and  610  r.p.m.,  were  placed  on  a  nearby  wharf  and  sup- 
pHed  salt  water  for  the  condensers  directly  from  the  Hudson 
River. 

To  operate  the  tunneling  shieds  three  hydraulic  power  pumps 
with  15-inch  duplex  cylinders  and  water  rams  2'  by  10  inches 
were  installed  at  each  power  house,  capable  of  giving  a  pressure 


NORTH   RIVER  TUNNELS 


61 


of  6000  pounds  per  square  inch.  One  pump  was  used  for  each 
tunnel  and  the  third  was  held  in  reserve.  The  usual  working 
pressure  carried  was  4500  pounds. 

Electric  light  and  power  were  supplied  by  two  direct  current 
generators,  delivering  at  240  volts  through  a  two-wire  system. 
These  units  were  driven  direct  by  a  vertical  tandem  compound 
engine  10  and  20  by  14  inches,  giving  150  h.p.  at  250  r.p.m. 

The  following  is  the  cost  of  operating  one  power  house  plant 
during  the  period  of  driving  the  shields,  excavating  and  metal 
lining,  in  a  24-hour  day: 


No. 

Labor 

Rate  per  day 

Amount 

6 

Engineers 

S3  00 

S18.00 

6 

Firemen 

2.50 

15.00 

2 

Oilers 

2.00 

4  00 

2 

Laborers 

2.00 

4.00 

4 

Pumpmen 

2.75 

II  .00 

2 

Electricians 

3  50 

7.00 

I 

Helper 

Total  per  dav 

3.00 

3.00 

S62.00 

Total  per  30  daj-s  .... 

S1860.00 

Supplies 


Coal,  14  tons  per  day 

Water 

Oil,  4  gals,  per  day 
Waste,  4  lbs.  per  day 
Other  supplies 


Total  per  da\- 
Total  per  30  days 


S55-78 
1673.00 


Cost  of  labor  and  supplies  for  one  day 
Cost  of  labor  and  supplies  for  30  days 


117.78 
3533  00 


The  cost  of  operating  the  power  plant  for  24  hours  during 
the  period  of  concrete  lining  was  S28.00  for  labor,  and  $61.00 
for  suppHes.  The  decrease  in  labor  cost  is  due  to  a  reduction 
in  working  force  as  but  two  engineers,  two  firemen,  two  pump- 


62 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


men,  one  foreman  electrician,  one  electrician  and  one  laborer 
were  required.  The  increase  in  cost  of  supplies  is  due  to  an 
increased  water  consumption. 

Crushed  rock  for  concrete  was  made  from  the  trap  rock 
excavated  from  the  Bergen  Hill  tunnel.  The  crushing  plant 
consisted  of  one  No.  6  and  one  No.  8  Austin  crusher,  driven 
by  a  single  cylinder,  horizontal  steam  engine  of  120  h.p.  The 
plant  was  capable  of  crushing  225  cubic  yards  of  stone  in  10 


Average  Thickness  of  Cover 

between  River  Lines 

25'0" 


SOUTH  TUNNEL  NORTH  TUNNEL 

Typical  Cross-section  of  North  River  Tunnels  Showing  Relative  Positions. 

hours.  Stone  from  the  pile  was  loaded  by  hand  into  scale 
boxes,  which  were  lifted  by  two  power  operated  derricks  into 
a  chute  above  the  No.  6  crusher.  From  this  crusher  the  stone 
was  hoisted  60  feet  by  a  bucket  conveyor  to  a  screen  above 
the  stone  bin.  This  screen  was  in  the  form  of  a  chute  placed 
at  45  degrees  and  perforated  with  2^-inch  round  holes.  As 
the  material  passed  over  this  chute  the  smaller  stone  dropped 


NORTH  IIIVER  TUNNELS 


63 


into  the  bin  and  the  larger  stone  passed  over  into  the  No.  8 
crusher,  from  which  it  was  carried  by  a  second  conveyor  to  the 
bin.  The  stone  was  loaded  into  dump  cars  of  3  cubic  yards' 
capacity  through  a  sliding  door  in  the  bottom  of  the  stone  bin, 
and  was  hauled  by  a  steam  dinky  engine  either  direct  to  the 
Weehawken  shaft  or  to  scows  for  transportation  to  New 
York. 

The  average  force  employed  at  the  rock  crushing  plant  was 
as  follows: 


1  foreman  at . 
24  laborers  at. 

2  laborers  at .  . 
4  laborers  at .  . 

1  engineer  at . 

2  engineers  at 


^300 
1-75 
I -75 
I -75 

Loading  scale  boxes  for  derricks 
Feeding  crushers. 
'To  keep  screens  clear. 

4.00 
3  50 

On  derricks. 

Owing  to  the  constant  breakdown  of  machinery,  chutes, 
etc.,  which  is  inseparable  from  stone  crushing  work,  a  repair 
gang  was  always  at  work,  consisting  of  either  three  carpenters 
or  three  machinists. 

The  approximate  cost  of  the  crushing  plant  was  as  follows: 

Machinery $5,850 

Lumber 3'305 

Labor  for  erecting 3,999 


Total $13,154 

The  cost  of  the  crushed  stone  at  Weehawken  was  about 
91  cents  per  cubic  yard,  made  up  as  follows: 

Cost  of  stone 22  cents 

Labor  in  operation  of  plant 31      " 

Plant  supplies 11    " 

Plant  depreciation 27    " 


Total 91  cents 

The  crushed  stone  of  the  Manhattan  shaft  cost  about  $1.04 
per  cubic  yard,  the  difference  of  13  cents  as  compared  with  the 
Weehawken  cost  being  made  up  by  the  cost  of  transfer  across 


64      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

the  river,  amounting  to  8  cents,  and  cost  of  transfer  from  the 
dock  to  the  shaft,  amounting  to  5  cents.  The  stone  for  crush- 
ing was  purchased  from  the  contractor  on  the  Bergen  Hill 
tunnels. 

In  the  design  of  the  tunneling  shields  for  driving  the  tunnels 
under  the  river  the  chief  points  to  be  kept  in  mind  were  ample 
strength,  easy  access  to  the  working  face  combined  with  ease 
and  quickness  of  closing  the  diaphragm,  and  general  simpHcity. 
Four  of  these  shields  were  used,  one  at  each  end  of  each  of  the 
tunnels. 

They  were  15  feet  iirk  inches  long,  exclusive  of  the  hood, 
and  23  feet  6^  inches  in  external  diameter.  The  outer  skin 
or  shell  was  2|  inches  thick,  made  up  of  two  f-inch  plates  with 
a  |-inch  plate  between,  butt-jointed  and  flush-rivetted  inside 
and  out.  The  interior  framing  consisted  of  two  floors  and  three 
vertical  partitions,  forming  nine  compartments  giving  access 
to  the  face.  They  were  provided  with  pivoted  segmental  doors. 
Forward  of  the  back  end  of  the  jacks  the  shield  was  stiffened 
by  an  annular  girder  surrounding  the  skin,  and  in  the  space 
between  the  stiffeners  were  set  24  hydraulic  rams,  used  to  force 
the  shield  ahead  by  pressure  exerted  against  the  last  erected 
ring  of  the  metal  lining. 

A  cast  steel  segmental  cutting  edge  was  attached  to  the 
periphery  of  the  forward  end  of  the  shield.  The  maximum 
and  minimum  overlap  of  the  shield  over  the  metal  lining  of  the 
tunnel  was  6  feet  4I  inches  and  2  feet,  respectively.  To  pass 
through  the  varying  ground  before  entering  the  true  sub- 
river  silt,  a  detachable  hood  in  nine  sections  was  extended  2 
feet  I  inch  beyond  the  cutting  edge  and  from  the  top  down  to 
the  level  of  the  upper  platform. 

The  weight  of  the  structural  portion  of  each  shield  was  135 
tons;  of  the  hydraulic  rams  and  erectors  58  tons;  and  of  the 
complete  shield  193  tons.  The  hydrauHc  apparatus  was  designed 
for  a  maximum  pressure  of  5000  pounds  per  square  inch  and 
a  test  pressure  of  6000  pounds.  Each  of  the  24  rams  was  8^ 
inches  in  diameter  by  38  inches  stroke.  The  average  pressure 
used   upon   them   was   3500   pounds   per   square   inch.     With 


NORTH  RIVER  TUNNELS 


65 


a  water  pressure  of  5000  pounds  per  square  inch  the  force  of 
one  ram  was  275,000  pounds  and  of  the  total  number  of  24 
rams  6,600,000  pounds  or  3300  tons,  giving  an  equivalent  pres- 
sure of  15,200  pounds  per  square  foot  of  face,  or  105  pounds  per 
square  inch.     The  rams  developed  a  tendency  to  bend  under 


The  bore  eegment  witliaut 
the  moveable  part  is  covered 
with  lU  cement  moctar  instead 
.._^ ,__         of  concreto, 

Cast-sieel  plug  removed  and  space  filled  with  sand 
wtich  must  be  thoroughly  compactecf  under  the  cover 


Cross-section  of  P.R.R.  North  River  Tunnel,  Sho\\'ing  Construction  and 

Dimensions. 


the  severe  test  of  moving  the  shield,  all  closed,  through  the  river 
silt.  It  is  probable  that  a  piston  10  inches  in  diameter  would 
have  been  better  adapted  for  this  work  than  those  of  8|  inches 
used. 

The  floors  of  the  two  platforms,  of  which  there  were  eight. 


66      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

formed  by  the  divisions  of  the  platforms  by  the  upright  fram- 
ing, could  be  extended  forward  2  feet  9  inches  in  front  of  the 
cutting  edge  or  8  inches  in  front  of  the  hood.  This  forward 
movement  was  produced  by  hydraulic  jacks.  The  sliding 
platform  could  sustain  a  load  of  7900  pounds  per  square  foot, 
which  equalled  the  maximum  head  of  ground  and  water  com- 
bined. Each  sHding  platform  was  actuated  by  two  single- 
acting  rams,  3I  inches  by  2  feet  9  inches.  With  a  hydraulic 
pressure  of  5000  pounds  the  forward  force  of  each  pair  of 
rams  on  each  platform  was  96,000  pounds.  As  the  area  of 
the  nose  of  the  platform  was  1060  square  inches  the  reaction 
was  90  pounds  per  square  inch  or  13,040  pounds  per  square 
foot. 

Each  shield  was  fitted  with  a  single  erector  mounted  on  the 
rear  of  the  diaphragm.  This  consisted  of  a  box-shaped  frame 
mounted  on  a  central  shaft  revolving  on  bearings  attached  to 
the  shield.  Inside  of  this  frame  was  a  differential  hydraulic 
plunger,  4  inches  and  3  inches  by  48  inches  stroke.  To  the 
plunger  head  were  attached  two  channels  sliding  inside  the  box 
frame,  and  to  the  projecting  end  of  these  the  grips  were  attached. 
The  opposite  end  of  the  box  frame  carried  a  counterweight 
which  balanced  about  700  pounds  of  the  tunnel  segment  at  a 
radius  of  11  feet.  The  erector  was  revolved  by  two  single- 
acting  rams  fixed  horizontally  to  the  back  of  the  shield  above 
the  erector  pivot,  operating  through  double  chains  and  chain 
wheels  keyed  to  the  erector  shaft.  With  a  hydraulic  pressure 
of  5000  pounds  the  following  are  some  of  the  figures  connected 
with  the  erector: 

Weight  of  heaviest  tunnel  segment 2,584  lbs. 

Weight  of  erector  plunger  and  grip 616  '' 

Total  weight  to  be  handled  by  the  erector 

ram 3,200 

Total  force  in  erector  ram  moving  from  cen 

ter  of  shield 35,ooo 

Total  force  in  erector  ram    moving  toward 

center  of  shield 27,500 


'^^yM-M 


Ai 


Locks,  P 


SECTION   AV 


i 


i 


NORTH   KIVER  TUNNELS  67 

Maximum  net  weight  at  1 1  ft.  radius  to  be 

handled  by  turning  rams 1,884  lbs. 

Total  force  of  each  rotating  ram  at  5000  lbs 

per  square  inch 80,000  ' ' 

Load  at  II  ft.  radius  equivalent  to  above.  .     3,780  " 


CHAPTER  X 

NORTH  RIVER  TUNNELS  OF  THE  PENNSYLVANIA  RAILROAD 

{Continued.) 

On  the  New  York  side  the  shields  were  built  inside  the  iron 
lining  of  the  shield  chambers,  and  no  false  work  was  required  as 
the  necessary  tackle  was  simply  slung  from  the  iron  lining. 
On  the  Weehawken  end  erecting  was  done  in  the  bare  rock 
excavation  and  false  work  was  required.  To  assemble  and 
rivet  each  shield  took  about  two  weeks,  the  riveting  being  done 
with  pneumatic  tools  using  compressed  air  from  the  tunnel 
supply.  When  the  structural  steel  work  was  completed  the 
shields,  weighing  113  tons  each,  were  jacked  to  grade  level. 
While  the  hydraulic  fittings  were  being  put  in,  the  shields  were 
moved  forward  on  a  cradle  built  of  concrete  with  imbedded  steel 
rails,  upon  which  the  shield  was  driven  for  the  distance  in  which 
the  tunnel  was  in  solid  rock.  The  installation  of  the  hydraulic 
fittings  took  from  four  to  six  weeks  per  shield  and  brought  the 
finished  weight  up  to  193  tons. 

When  the  shield  was  finished  and  in  position  the  first  two 
rings  of  the  segmental  tunnel  lining  were  erected  in  the  tail 
of  the  shield.  These  were  firmly  braced  to  the  rock  and  chamber 
lining.  The  shield  was  then  shoved  ahead  by  its  own  jacks 
and  another  ring  erected,  and  this  process  was  continued  indef- 
initely. In  the  description  of  the  methods  of  work  in  the  shield- 
driven  tunnel  which  follows,  the  subject  will  be  discussed  in 
different  sections  determined  by  the  different  conditions  met 
at  the  working  face. 

In  working  in  a  full  rock  face,  excavation  so  far  as  possible 
was  done  before  the  shields  were  installed.  On  the  New  York 
side  about  146  feet  of  tunnel  was  completely  excavated,  with 
71  feet  of  bottom  heading  beyond  that.     At  the  Weehawken 

68 


NORTH  RIVER  TUNNELS  69 

end  58  feet  of  tunnel  and  40  feet  of  heading  were  driven.  This 
was  done  to  avoid  handling  the  rock  through  the  narrow  shield 
doors.  Test  holes  were  driven  ahead  to  determine  the  depth 
of  rock  cover.  At  Weehawken  on  February  14,  1905,  a  blast 
broke  through  the  rock  and  the  mud  flowed  in,  filling  the  tunnel 
for  half  its  height  for  a  distance  of  300  feet  back  from  the  face. 

Through  rock  section  the  shield  was  moved  upon  either 
two  or  three  rails  imbedded  in  concrete.  Where  the  full  tunnel 
section  had  been  excavated  it  was  only  necessary  to  trim  off 
the  small  projections  of  rock.  In  the  portions  where  a  bottom 
heading  only  had  been  driven,  excavation  was  completed  just 
in  front  of  the  shield,  the  drilling  below  axis  level  being  done 
in  the  heading  and  above  that  from  the  front  sliding  platforms. 
Shallow  holes  were  drilled  and  spaced  closely;  light  charges 
of  powder  only  being  used  to  lessen  the  chance  of  damage  to 
the  shield.  In  this  work  the  small  shield  doors  hampered 
operations  and  larger  bottom  openings,  which  would  permit 
of  subdivisions  or  of  being  partly  closed  in  soft  ground,  would 
have  been  an  advantage.  But  owing  to  the  greater  part  of  the 
rock  having  been  excavated  before  the  shields  were  installed 
the  quantity  thus  handled  was  small.  The  space  outside  the 
lining  was  grouted  with  a  one-and-one  mixture  of  Portland 
cement  and  sand.  Large  voids  were  hand  packed  with  stone 
before  grouting. 

A  typical  working  gang  is  given  herewith.  Two  gangs 
were  worked  in  each  shield  in  24  hours  in  lo-hour  shifts.  This 
portion  of  the  work  was  done  under  normal  air  pressure. 

General 

Tunnel  superintendent,  V  time ....   $200.00  per  month 

Assistant  superintendent 5.00     per  day 

General  foreman 5.00  ' ' 

Electrician,  h  time 3.50  " 

Electrician's  helper,  i  time 3.00  " 

Pipe  fitter,  h  time 3.00  ' ' 

Pipe  fitter's  helper,  ^  time 2.75  " 

Total About  $20  per  shift. 


70      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

Drilling 

Foreman $5.00  $  5.00 

3  drillers 4.00  12.00 

3  drillers'  helpers 3.00  9.00 

I  nipper 2.50  2.50 

I  water  boy,  ^  time 2.50  1.25 

I  powder  boy,  h  time 2.75  1.38 

Cost  per  shift $31-13 

Mucking 

Foreman $3-5o         $3.50 

8  muckers 2.75  22.00 

Cost  per  shift $25.50 

Erecting  Iron  and  Driving  Shields 

I  erector  runner $4.00         $4.00 

3  iron  workers 3.00  9.00 

Cost  per  shift $13.00 

Cost  of  shield  gangs  per  shift $89.63 

The  rate  of  progress  obtained  was  4.2  feet  per  day  per  shield 
where  most  of  the  excavation  had  been  done  beforehand  and 
2.1  feet  per  day  per  shield  where  no  advance  excavation  had 
been  done. 

When  the  shields  had  gotten  far  enough  away  from  the 
shield  chambers,  and  before  rock  cover  was  lost,  the  first  air- 
lock bulkhead  walls  were  put  in.  These  walls  and  their  fittings 
were  designed  to  withstand  an  air  pressure  of  50  pounds  per 
square  inch.  They  were  all  of  concrete  10  feet  thick  with  the 
exception  of  the  first  two,  which  were  only  8  feet  thick.  Each 
had  three  locks  capable  of  holding  men.  In  addition,  pipes 
were  built  in  to  give  access  to  the  cables  and  to  pass  pipes,  rails, 
etc.,  in  and  out.  When  each  tunnel  had  been  aavanced  about 
1200  feet  from  the  first  wall  a  second  wall  like  the  first  was  built. 
Thus  there  were  two  of  these  bulkhead  walls  at  each  end  of  each 


NORTH    RIVER  TUNNELS  71 

tunnel,  making  8  in  all.  The  second  bulkhead  was  simply  an 
added  safeguard  to  the  tunnel  and  permitted  the  air  pressure 
at  the  face  to  be  reduced  between  the  walls,  thus  lowering 
the  pressure  in  stages.  The  exercise  in  walking  between  the 
bulkheads  in  the  lower  pressure  was  found  to  be  beneficial  to 
the  health  of  those  working  in  the  compressed  air. 

When  rock  cover  became  dangerously  thin  air  pressures  of 
from  12  to  1 8  pounds  were  used,  this  being  found  sufficient 
to  stop  the  water  coming  from  the  gravel  on  top  of  the  rock. 
When  the  surface  of  the  rock  was  first  penetrated  the  soft  face 
was  held  by  horizontal  boards  braced  from  the  shield  until 
the  latter  could  be  advanced.  These  braces  were  then  taken 
out  and  replaced  by  others.  As  the  amount  of  soft  ground 
in  the  face  increased  the  system  of  timbering  was  gradually 
changed  to  one  using  2-inch  poling  boards  resting  on  top  of 
the  shield  and  supported  at  the  face  by  vertical  breast  boards, 
which,  in  turn,  were  held  by  walings  6  by  6  inches  braced  through 
the  upper  doors  to  the  iron  fining  and  from  the  sfiding  platforms 
to  the  shield.  In  driving  through  this  mixed  ground,  involving 
rock  and  mud,  a  typical  working  gang  was  as  follows.  In  this 
part  of  the  work  three  shifts  of  8  hours  each  were  employed. 

General 

^  tunnel  supt $300  per  month  $4.00  day 

Asst.  supt 5.00 

General  foreman 5.00 

i  electrician $3.50      "  1.75 

^  electrician's  helper ...  .     3.00      "  1.50 

i  pipe  fitter 3.25      "  1.63 

^  pipe  fitter's  helper ...  .     3.00      "  1.50 

Cost  per  8-hour  shift.  .  .  $20.38 

Drilling 

Foreman $5.00  day 

2  drillers $3.25  per  day  6.50   ' ' 

2  drillers' helpers 3.00      "  6.00  " 

Cost  per  8-hour  shift.  .  .  $17.50 


72       SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

Timbering 
2  timbermen $2.50  per  day  $5.00  day 

2  timbermen's  helpers .  .      2.00       "  4.00   " 

Cost  per  8-hour  shift.  .  .  $9.00 

Mucking 

Foreman $  3.50  day 

6  muckers $2.75  per  day  16.50   " 

Cost  per  8-hour  shift .  .  .  $20.00 

Erecting  Iron  and  Driving  Shield 
Erector  runner S3-5o  per  day 

3  iron  workers $3.00  9.00        " 

Cost  per  8-hour  shift.  .  .  $12.50 

Total  cost  of  labor  per  8-hour  shift .  .  79-38 

The  average  rate  of  progress  was  2.6  ft.  per  day. 

TunneUng  in  a  full  face  of  sand  and  gravel  was  encountered 
only  at  Weehawken,  and  two  systems  of  timbering  were  used. 
In  the  first  the  ground  was  excavated  2h  feet  ahead  of  the 
cutting  edge,  the  roof  being  held  by  longitudinal  poling  boards 
resting  on  the  outside  of  the  shield  skin  at  their  back  ends,  and 
on  vertical  breast  boards  at  the  forward  ends.  When  the 
upper  part  of  the  face  was  dry  it  was  held  by  vertical  breast 
boards  from  the  sHding  platforms  and  through  the  shield  doors 
to  cross  timbers  in  the  tunnel.  The  lower  part,  which  was 
always  wet,  was  held  by  horizontal  breast  boards  braced  through 
the  lower  shield  pockets  to  cross  timbers  in  the  tunnel. 

As  soon  as  the  rock  surface  was  penetrated,  and  the  sand 
and  gravel  encountered,  the  escape  of  air  was  enormously 
increased.  It  was  found  impossible  to  maintain  the  required 
pressure  even  with  the  three  compressors  working  to  the  limit 
of  their  capacity,  each  compressing  4400  cubic  feet  of  free  air 
per  minute  or  13,200  cubic  feet  in  all. 

To  decrease  this  leakage  of  air  a  large  quantity  of  straw 
and  clay  was  used  in  front  of  the  breasting.     This  diminished 


NORTH   RIYER  TUNNELS 


73 


the  loss  of  air,  but  a  large  quantity  still  escaped  through  the 
joints  of  the  iron  lining,  so  that  these  had  to  be  plastered  with 
Portland  cement.  Even  then  the  loss  was  too  great  and  it 
was  necessary  to  shut  down  one  tunnel  and  deliver  all  the  air 
to  the  other.  This  allowed  a  pressure  of  lo  pounds  to  be 
maintained  which,  though  less  than  the  hydraulic  head,  was 
sufficient  to  permit  progress  to  be  made.     The  timbered  face 


^H 

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Interior  of   Shield    in  P.R.R.    North    River  Tunnel,   Showing  Silt  Entering 
Through  One  Open  Door. 


was  never  grouted,  for  though  this  would  have  reduced  the 
loss  of  air,  it  would  have  cut  down  the  rate  of  progress  very  much. 
The  abnormally  increased  demand  upon  the  air  compres- 
sors to  supply  the  necessary  air  to  maintain  the  pressure  in 
the  tunnel  subjected  the  machines  to  a  most  severe  and  extended 
test  of  reliability  under  conditions  involving  extreme  speed  and 
greatly  augmented  load.  A  breakdown  would  have  meant 
the   loss   of    the   working   face.     This   extreme    condition   was 


74:      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

maintained  until  the  silt,  which  lay  above  the  sand  and  gravel, 
showed  in  the  roof,  when  the  escape  of  air  was  immediately 
reduced,  and  it  became  possible  to  work  the  two  faces  simulta- 
neously. 

In  driving  these  faces  a  t\'pical  gang  for  an  8-hour  shift 
was  as  follow^s: 

General 

I  General  supt $300.00  per  month ....  $4.00  per  day 

Assistant  supt 5.00       ' ' 

General  foreman 5.00       " 

I  electrician  and  helper  $3.50  and  $3.00.  ..  .  3.25       " 

^  pipe  fitter  and  helper     3.25  and  3.00 3.13       " 

Cost  per  8-hour  shift $20.38      ' ' 

Timbering 
3  timbermen $2.50 $7-5o  per  day 

3  timbermen's  helpers  2.00 6.00       " 

Cost  per  8-hour  shift $13.50       " 

Mucking 

Foreman $3-5o 

6  muckers $2.75 16.50 

Cost  per  8-hour  shift $20.00 

Erecting  Iron  and  Driving  Shield 

Erector  runner $3-25 

Foreman 4.00 

4  ironworkers S3. 00 12.00 

Cost  per  8-hour  shift $19.25 

Total  cost  of  labor  8-hour  shift $73-i3 

The  average  rate  of  advance  in  sand  and  gravel  was  5.1 
feet  per  day  for  each  shield.  As  soon  as  the  silt  was  encoun- 
tered in  the  upper  part  of  the  face  the  speed  increased  to  7 
feet  .per  day  per  shield. 


NORTH  RIVER  TUNNELS  75 

In  passing  under  the  river  wall  at  Weehawken,  where  the 
bulkhead  consisted  only  of  a  crib-work  supported  on  piles, 
the  latter  obstructed  the  advance  of  the  shield  but  were  easily 
cut  out.  On  the  New  York  side  the  conditions  were  not  so 
favorable.  Here  the  heavy  masonry  bulkhead  was  supported 
on  piles  and  rip-rap.  The  top  of  the  shield  came  about  6  feet 
above  the  bottom  of  the  rip-rap  and  the  open  spaces  between 
the  stones  allowed  a  free  flow  of  water  directly  from  the  river. 
As  soon  as  the  cutting  edge  entered  the  rip-rap  there  w-as  a 
blowout,  the  air  escaping  freely  to  the  ground  surface  behind 
the  bulkhead  and  to  the  river  in  front  of  it.  Clay  puddle  or 
mud,  made  from  the  excavated  silt,  was  used  in  large  quantities 
to  fill  the  voids  between  the  stones  in  the  working  face.  The 
excavation  of  this  rip-rap  w'as  carried  on  by  the  removal  of 
one  stone  at  a  time,  the  spaces  between  the  newly  exposed  stone 
being  immediately  plugged  with  mud.  When  the  shield  had 
advanced  its  own  length  in  the  rip-rap  another  place  for  the 
escape  of  air  was  exposed  at  its  rear  end.  This  leakage  was 
stopped  with  mud  and  cement  sacks  at  the  forward  end  of  the 
last  ring  of  the  tunnel. 

As  long  as  the  shield  was  stationary  it  was  possible,  by 
using  these  methods  and  by  exercising  care,  to  prevent  the 
excessive  loss  of  air,  but  while  the  shield  was  being  shoved 
ahead  the  difficulties  were  much  increased,  as  the  movement 
of  the  shield  displaced  the  bags  and  mud  as  fast  as  they  were 
placed.  It  was  only  by  shoving  slowly  and  having  a  large 
number  of  men  looking  out  for  leaks  and  stopping  them  that 
excessive  air  loss  could  be  avoided. 

In  erecting  the  iron  lining,  as  a  segment  was  placed  in 
position  it  was  necessary  to  clean  ofT  the  forward  surface  of 
the  previous  ring  and  the  adjacent  portion  of  the  tail  of  the 
shield.  This  was  always  accompanied  by  a  slight  blow  and  for 
some  time  the  air  pressure  in  the  tunnel  dropped  from  25  to 
20  pounds.  In  other  words,  every  time  a  segment  was  placed 
the  air  pressure  dropped  from  greater  than  the  balancing  pres- 
sure to  less;  and  on  two  occasions  the  blow  became  so  great, 
and  the  tunnel  pressure  was  so  much  reduced,  that  the  water 


76      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

from  the  river  rushed  in  and  was  not  stopped  until  it  had  risen 
about  4  feet  in  the  tunnel  invert.  On  such  occasions  the  sur- 
face of  the  river  was  greatly  disturbed,  often  rising  more  than 
20  feet  in  the  air  in  the  form  of  a  geyser.  A  large  quantity 
of  grout  (about  2500  barrels  of  cement  and  a  similar  amount 
of  sand  in  the  north  tunnel,  and  1000  barrels  in  the  south  tunnel) 
was  used  at  this  point.  It  was  forced  through  the  tunnel  lin- 
ing immediately  behind  the  shield,  greatly  reducing  the  loss 
of  air  and  binding  the  rip-rap  together. 

When  the  shield  had  traveled  25  feet  through  the  rip-rap 
the  piles  supporting  the  bulkhead  were  met.  One  hundred 
of  these,  spaced  on  three-foot  centers,  were  cut  out  of  the  path 
of  the  shield  in  a  distance  of  35  feet.  In  passing  through  the 
piling  no  timbering  was  done  and  the  piles  supported  the  face 
effectively. 

When  the  river  line  had  been  passed  the  blow  still  continued, 
and  as  there  was  no  heavy  ground  above  the  tunnel  the  light 
silt  was  carried  away  into  the  water  by  the  escaping  air.  At 
one  time  the  cover  over  the  crown  of  the  tunnel  was  reduced 
to  such  an  extent  that  for  a  distance  of  30  feet  there  was 
less  than  10  feet  of  very  soft  silt  overlying  and  in  some  places 
none  at  all.  The  shield  was  stopped  and  the  air  pressure 
reduced  to  less  than  the  balancing  pressure.  The  blow  then 
stopped  and  about  28,000  cement  bags  filled  with  mud  w^ere 
dumped  into  the  hole.  They  were  then  weighted  down  with 
rip-rap.  This  sealed  the  blowout  and  the  work  was  continued 
without  further  disturbance  from  this  source.  The  working 
force  employed  here  was  similar  to  that  employed  in  the  sand 
and  gravel  sections. 


CHAPTER   XI 

NORTH    RIVER    TUNNELS    OF    THE    PENNSYLVANIA    RAILROAD 

{Co)ili>iiied.) 

In  the  North  River  tunnels,  between  Tenth  Avenue  and  the 
large  shaft  at  Weehawken,  N.  J.,  Ingersoll-Rand  drills,  sizes 
A-86,  C-24,  E-24  and  F-24,  were  used.  While  the  air  pressure 
at  the  power  house  was  100  pounds,  the  effective  pressure  at  the 
drills  was  only  80  pounds.  The  drill  steel  used  was  ij  to  i|- 
inches,  octagon.  The  holes  were  started  with  a  3^-inch  diame- 
ter and  bottomed  at  2f-inch  diameter  at  a  depth  of  10  feet. 
The  powder  used  on  the  New  York  side,  because  of  the  prox- 
imity of  buildings  and  lack  of  heavy  rock  cover,  was  40  per 
cent  forcite.  The  holes  were  closely  spaced  and  light  charges 
of  explosive  used. 

The  amount  of  excavation  done  was  11  per  cent  greater 
than  that  paid  for.  For  a  period  covering  five  months  and 
12,900  cubic  yards  of  excavation  the  record  of  drilling,  and 
amount  of  powder  used  per  cubic  yard  of  excavation,  were 
as  follows: 


Feet  of  hole  drilled  per 
cu.  yd.  of  excavation. 

Pounds  of  powder  used  per 
cu.  yd.  of  excavation. 

Portion  of   excavation. 

is'  14" 

Span 
Twin  T. 

19'  6" 

Span 

Twin  T. 

24'  6" 

Span 

Twin  T. 

is'  4" 

19'  6" 

24'  6" 

Wall  plate  heading  (i) .  .  . 
Total  heading 

13.00 
7.87 
5-97 
9.82 

10.97 
8.17 

6.15 
15.96 

10.97 
7.81 
7.56 

iS.io 

3-77 

2-31 

0.94 
1.84 

2.85 
2.02 

0-93 
2.40 

2.85 
1.7S 
I    13 

Bench  and  raker  bench  (i) 
Trenclj  (i) 

2-73 

Average  for  section  (i) .  .  . 

6.69 

7-43 

8-95 

1.28 

1.30 

1-45 

Actual  amount  (2) 

.82 

7.27 

8.95        1.22     1     1.24 

1 .  27 

77 


78 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


In  the  foregoing  table  the  items  marked  (i)  give  the  figures 
from  a  typical  cross-section;  the  item  marked  (2)  gives  the 
actual  amount  of  drilling  done  and  powder  used  per  cubic 
yard  for  the  whole  period  of  five  months.  But  as  this  included 
280  feet  of  heading  and  only  220  feet  of  bench,  the  average 
figures  (especially  for  explosives)  are  too  low. 

The  following  figures  cover  the  cost  of  driUing  and  blasting 
in  the  rock  tunnel  excavation  under  Thirty-second  Street,  east 
of  the  cut-and-cover  section.  They  cover  five  months  of  time 
and  11,649  cubic  yards  of  material  paid  for.  The  total  amount 
of  drilling  done  was  86,749  feet  in  3206  drill  shifts  of  10  hours 
each.  The  average  footage  of  hole  per  man  per  hour  was  3.02 
in  the  heading  and  2.71  on  the  bench.  The  cost  of  labor  only 
for  drilling  and  sharpening  steels  was  $25,283,  equivalent  to 
29  cents  per  lineal  foot  or  $2.17  per  cubic  yard  paid  for.  The 
total  amount  of  powder  used  was  14,444  pounds,  representing 
a  cost  of  14  cents  per  cubic  yard,  with  dynamite  at  11  cents 
per  pound.  The  table  below  gives  an  analysis  of  the  drilling 
operations : 


One  heading. 


Quartz. 


Hrs 


M, 
0.38 
4  52 
1 .40 


Setting  up 

Drilling 

Necessary  delay 

Unnecessary  delay 

Taking  down  machine 0.05 

Loading  and  firing o  .04 

Total  drilling 7- 19 

Mucking 2.41 


Total 

Feet  drilled  per  shift 

Feet  drilled  per  working  hour  . 


10.00 

22.00 

2.86 


Hard 
mica 
schist. 


Hrs.    M 
0.15 


1-45 


10.00 

42.00 

4.20 


Bench. 


Quartz. 


Hrs.    M. 
1.23 

5-57 
2.23 

0-15 
0-5 
0.07 
10. o 


10.00 
259 
2-59 


Mica 

schist 

medium. 


Hrs.  M, 
1 .10 
6.08 
1-50 
0.12 
0.07 
0.07 

9-34 
0.26 


10.00 

22.  22 

2.32 


Center  trench. 


Mica  schist. 


Soft. 


Hrs.  M. 
1.58 
5-53 
^■33 
0.06 
0.12 
0.30 
9.12 
0.48 


10.00 

22.00 

2-39 


Medium. 


Hrs.    M. 
I  .10 
6.40 
1. 17 

O.IO 

0.20 

0.23 

10.00 


10.00 

26.44 

2.64 


NORTH   RIVER  TUNNELS 


79 


The  foregoing  figures  are  the  result  of  67  observations. 
It  was  found  that  the  average  time  and  percentage  per  lo-hour 
shift  for  each  operation  were  as  follows: 

Setting  up i  hr 

Drilling 5 

Necessary  delay i 

Unnecessary  delay o 

Taking  down  machine .  .  .  .  o 

Loading  and  firing o 

Total  drilling 9 

Mucking o 

While  the  shield  chambers  were  being  excavated  bottom 
headings  were  run  along  the  lines  of  the  river  tunnels,  and 
continued  until  the  lack  of  rock  cover  prevented  their  being 
driven  further.  The  typical  working  force  in  the  shield  cham- 
bers was  as  follows : 


ir.    8  min. 

or  11.3% 

"    58     " 

59-7 

"    53     " 

19.9 

"   07     " 

I.I 

"   09     " 

1-5 

"    12     " 

2 

"    27     " 

94-5 

"   33     '' 

5-5 

Drilling  and  Blasting — Ten-hour  Shifts 


I  foreman at 

6  drillers 

6  drillers'  helpers 

I  blacksmith 

I  smith's  helper 

I  powder  man 

I  water  boy 

I  nipper 

I  machinist 

I  machinist's  helper 


553-50 
3.00 
2.00 

3-50 
2.25 
2.00 
2.00 
2.00 
3.00 
1.80 


$3-50 
18.00 
12.00 

3-50 
2.25 
2.00 
2.00 
2.00 
3.00 
1.80 

$50.05 


Mucking 

I  foreman at  $3.00  $3.00 

16  muckers "      2.00  32.00 


$35.00 


80  SUBWAYS  AND   TUNNELS  OF  NEW   YORK 

ANALYSIS   OF   COST  OF   DRILLING 


Cost  per  foot  of  hole  drilled. 


Cost  per  drill  shift. 


Item  of  cost. 


IS'4" 


Drilling  labor  ........ 

Sharpening 

Drill  steel  (5"  per  drill 

shift) 

Drill  repairs 

High    pressure    air 

(estimated) 

Totals 


50.25 
0.02 


0.007 
0.002 


0.05 


0.35 


I9'6' 


^0.2» 
0.02 


0.007 
0.02 


0.04 


0.38 


,,,,   I  Aver- 
246      I     age. 


F0.31     $0.28 
O.OI    I  0.016 

1 
0.006!    0.007 


0.07 


0.41 


0.07 


IS'4" 


I9'6" 


56.95 
0-53 


o.  19 
0.61 


1-39 


0.385,  967 


7-75 
0.42 

o.  20 
0.59 

1.86 


24'6" 


Aver- 


7.60    $7.45 

0.34       0.43 

j 

0.15       0.19 
0.42       0.54 


I  .67 


10.43 


COST  OF  EXCAVATION  OF  LAND  TUNNELS,  IN  DOLLARS  PER  CUBIC 

YARD 


Manhattan. 


Weehawken. 


Total  yardage 

and  average 

cost. 


Cubic  yards  e.xcavated 

Labor : 

Surface  transport 

Drilling  and  blasting 

Mucking 

Timbering 

Total  labor 

Material: 

Drilling 

Blasting 

Timber 

Total  material 

Plant  running 

Surface  labor,  repairs  and  main- 
tenance   

Field  office  administration 

Total  field  charges 

Chief  office  administration 

Plant  depreciation 

Street  and  building  repairs 

Total  average  cost  per  cubic 
yard 


42289 

$0.49 

2-37 
2.49 
0.87 

$6.22 


$0.15 
0.21 
0.39 

$0.75 

$0.76 

015 
I  OS 

$8.96 

0.34 
0.66 
o.  27 


83II 

1:0.87 

1-55 


S)0.i5 
o.  21 
o.  20 

$0.56 

$0.65 

0.08 
1. 18 

S7.I5 
0.38 
1 .01 


51600 

fo.55 
2.  24 
2.42 
0.76 

$5-97 


550.15 
o.  21 
0.36 

$0.72 

$0.74 


0.14 

1.07 

$8.64 

0.34 

0.72 

0.23 

iIO.23 


■54 


■93 


NORTH    KIVEK  TUNNELS  81 

In  working  in  the  shield  chambers  in  a  full  face  of  rock  as 
much  as  possible  of  the  rock  excavation  was  done  before  the 
shields  were  installed  in  order  to  avoid  handling  the  rock 
through  the  narrow  shield  doors.  The  typical  working  gang 
in  the  shields,  of  which  there  were  two  gangs  per  shield  per 
24  hours  working  in  two  lo-hour  shifts,  was  as  follows: 

General 

2  tunnel  supt at  $200.00  per  month 

I  assistant  tunnel  supt ''  5.00  per  day 

I  general  foreman "  5.00 

^  electrician "  3.50 

h  electrician's  helper "  3.00 

i  pipe  fitter "  3.00 

h  pipe  fitter's  helper ''  2.75 

Drilling 

I  foreman at  $5.00  per  day 

3  drillers ' '  4.00  ' ' 

3  drillers'  helpers. "  3.00  " 

I  nipper "  2.50  " 

i  water  boy "  2.50  " 

^  powder  boy "  2.75  " 

Mucking 

I  foreman at       $3.50  per  day 

8  muckers ''  2.75       " 

The  duties  of  these  gangs  were  as  follows:  The  tunnel 
superintendent  looked  after  both  shifts  of  one  shield;  the 
assistant  or  walking  boss  had  charge  of  all  work  in  the  tunnel 
in  one  shift;  the  general  foreman  had  charge  of  the  labor  at  the 
face;  the  electrician  looked  after  repairs,  extensions  of  the 
cables  and  lamp  renewals;  the  pipe  fitters  worked  in  both 
tunnels,  repairing  the  leaks  in  pipes  between  the  power  house 
and  working  faces,  extending  the  pipe  lines  and  attending  to 
shield  repairs;  in  the  latter  work  the  erector  runner  helped. 
The  drillers  stuck  to  their  own  jobs,  which  were  not  subject  to 


82      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

interruption  as  long  as  the  bottom  headings  lasted.  One  water 
boy  and  one  powder  boy  served  two  tunnels.  The  muckers 
helped  the  iron  men  put  up  the  rings  of  the  casing,  as  well  as 
looking  after  their  own  work  in  cleaning  out  the  face.  The 
rate  of  progress  obtained  was  4.2  feet  per  day  per  shield  where 
most  of  the  excavation  had  been  done  beforehand;  and  2.1  feet 
per  day  per  shield  where  no  previous  work  had  been  done. 

When  the  rock,  gravel  and  hard-pan  gave  place  to  a  full 
face  of  silt,  the  timber  was  removed,  all  the  shield  doors  were 
opened,  and  the  shield  was  shoved  forward  into  the  ground 
without  any  excavation  being  done  by  hand  ahead  of  the 
diaphragms.  As  the  shield  advanced  the  silt  was  simply  forced 
through  the  open  doors  into  the  tunnel.  After  the  work  had 
progressed  in  this  way  for  some  time,  taking  in  about  90  per 
cent  of  the  full  volume  of  the  tunnel  excavation  per  foot  of 
advance,  the  air  pressure  was  raised  from  20  to  22  pounds. 
As  a  result  the  silt  in  the  face  got  harder  and  flowed  less  readily 
through  the  shield  doors;  and  the  amount  taken  in  fell  to  about 
65  per  cent  of  the  full  volume.  As  this  mode  of  operation 
caused  a  disturbance  of  the  surface  the  air  pressure  was  lowered 
to  16  pounds,  when  the  muck  became  softer  and  the  full  volume 
of  excavation  was  taken  in.  The  pressure  was  later  raised  to 
20  pounds. 

The  forcing  of  the  shield  through  the  silt  resulted  in  raising 
the  bed  of  the  river  in  an  amount  depending  on  the  quantity 
of  material  brought  into  the  shield.  If  the  whole  volume  of 
excavation  was  being  brought  in,  the  surface  of  the  river  bed 
was  not  affected.  When  about  50  per  cent  of  the  whole  volume 
was  being  taken  in  the  river  bed  raised  about  3  feet;  and  when 
the  shield  was  being  driven  blind  the  bed  raised  about  7  feet. 
The  opening  of  doors  in  the  shield  was  regulated  to  take  in  the 
minimum  quantity  of  muck  and  cause  no  surface  disturbance. 
In  the  north  Manhattan  tunnel  all  the  doors  were  usually 
open;  in  the  south  tunnel  five  or  six  of  the  nine  doors  were 
generally  open. 

1  From  the  paper  by  B.  H.  M.  Hewett  and  W.  L.  Brown,  before  the  American 
Society  of  Civil  Engineers,  June,  igio. 


NORTH  RIVER  TUNNELS  83 

As  soon  as  the  south  shield  had  passed  the  river  bulkhead 
at  Weehawken  the  silt  was  found  to  be  much  softer  than  behind 
the  wall.  It  was  like  a  fluid  in  many  of  its  properties  and  this 
fluidity  could  be  varied  by  changing  the  air  pressure  in  the 
shield  chamber.  When  the  air  pressure  was  equal  to  the 
weight  of  the  overlying  water  and  silt,  the  silt  stiffened  to  about 
the  consistency  of  a  very  soft  clay.  When]  the  pressure  was 
reduced  to  12  or  15  pounds  it  became  sufficiently  fluid  to  flow 
through  a  i^-inch  grout  hole  at  a  rate  running  up  as  high  as 
50  gallons  per  minute.  This  was  a  condition  which  had  been 
looked  forward  to  by  the  contractor  and  it  was  anticipated  that 
the  shield  doors  could  be  closed  and  the  shield  driven  across 
the  river  without  taking  in  a  shovelful  of  muck.  This  had  been 
done  in  driving  the  Hudson  and  Manhattan  Railroad  Company's 
tunnels  between  Hoboken  and  New  York  City,  but  when  the 
doors  were  all  closed  and  the  shield  shoved  forward  the  tunnel 
immediately  began  to  rise  in  spite  of  the  heaviest  downward 
lead  which  the  clearance  at  the  back  of  the  shield  would  permit. 

The  pressure  caused  by  the  shield  displacing  the  ground 
as  it  advanced  caused  the  iron  tunnel  lining  to  rise  about  2 
inches  and  it  became  distorted,  the  horizontal  diameter  decreas- 
ing and  the  vertical  diameter  increasing  by  as  much  as  i  j  inches. 
The  shield  was  stopped  and  the  hood  removed  as  it  was  thought 
that  the  latter  was  producing  these  effects.  Driving  was  then 
resumed,  but  the  same  troubles  continued  and  it  was  not 
found  possible  to  keep  to  grade. 

By  opening  the  doors  and  taking  in  a  portion  of  the  material 
these  difficulties  were  overcome.  It  was  found  that  the  level 
of  the  shield  could  be  regulated  by  varying  the  proportion  of 
silt  admitted  through  the  doors.  This  quantity  ranged  from 
none  at  all  to  the  full  volume  displaced  and  averaged  about 
7,7,  per  cent.  The  muck  flowed  into  the  tunnel  in  a  thick  stream, 
and  by  regulating  the  advance  of  the  shield  the  flow  was  pro- 
portioned to  the  time  which  was  required  to  load  it  into  cars. 
In  driving  through  silt  the  typical  gang  per  shift  of  eight  hours 
per  shield  was  as  follows: 


84      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

General 

J  tunnel  supt.  at  $300  per  month $4.00  per  day 

Asst.  supt 6.00 

General  foreman 5.00      ' ' 

Foreman 4.00 

^  electrician  and  helper,  $3.50  and  3.00  3.25      " 

2  pipe  fitters,  $3.50 7.00      " 

2  pipefitters' helpers,  $3.25 6.50      " 

Cost  per  8-hour  shift 35.75 

Mucking 

Foreman $4.00  per  day 

6  muckers,  $3.00 18.00      " 

Cost  per  8-hour  shift $22.00 

Erecting  Iron  and  Driving  Shield 

Foreman $4.00  per  day 

Erector  runner 3.50 

4  iron  workers,  $3.00 12.00 

3  laborers,  $3.00 9.00      ' ' 

Cost  per  8-hour  shift $28.50 

The  total  cost  of  labor  per  8-hour  shift  was  $85.75.  Three 
shifts  of  8  hours  each  were  worked  under  an  average  air 
pressure  of  25  pounds.  The  rate  of  progress  in  the  silt  under 
the  river  was  2^  feet  (the  width  of  a  ring)  in  every  3  hours  and 
21  minutes  or  about  one  foot  in  i  hour  and  20  minutes.  This 
was  exclusive  of  the  time  during  which  work  was  suspended. 
The  average  daily  advance,  including  all  delays,  was  10.8  feet 
per  day. 

The  junction  of  the  shields  under  the  river  was  made  as 
follows:  When  the  two  shields  of  one  tunnel,  which  had  been 
driven  from  opposite  sides  of  the  river,  approached  within 
10  feet  of  each  other  the  shields  were  stopped  and  a  lo-inch  pipe 
was  driven  between  them  in  order  to  make  a  final  check  on  lines 


NORTH  RIVER  TUNNELS  85 

and  levels.  The  first  traffic  established  was  the  passage  of  a 
box  of  cigars  through  this  pipe. 

One  shield  was  then  started  up  with  all  doors  closed  while 
the  doors  on  the  stationary  shield  ahead  were  opened  so  that 
the  muck  driven  forward  by  the  moving  shield  was  taken  in 
through  the  doors  of  the  stationary  shield.  This  was  con- 
tinued until  the  cutting  edges  met.  All  doors  in  both  shields 
were  then  opened  and  the  shields  mucked  out.  The  cutting 
edges  were  removed  and  the  shields  advanced  till  their  outer 
skins  met.  The  interior  framing  and  everything  except  the 
outer  skin  of  the  shields  was  removed.  The  iron  lining  was 
then  built  up  inside  of  the  skins,  concreted  and  grouted  outside. 

The  single  erector  attached  to  the  center  of  the  shield  was 
capable  of  erecting  the  iron  lining  as  fast  as  it  could  be  brought 
into  the  tunnel.  The  individual  segments  varied  in  weight 
from  2060  to  2580  pounds.  The  average  time  spent  in  erect- 
ing and  bolting  up  for  the  whole  length  of  the  tube  tunnels 
was  2  hours  and  15  minutes  per  ring.  Each  ring  was  2  feet 
6  inches  in  width  by  23  feet  outside  diameter. 

After  the  metal  lining  had  been  built  completely  across  the 
river  in  both  tunnels  the  work  of  making  it  water-tight  was 
taken  up.  This  consisted  in  forming  a  rust  joint  between  the 
plates  with  a  mixture  of  sal-ammoniac  and  iron  borings,  and 
in  taking  out  each  bolt  and  placing  around  the  shank  under 
the  washer  at  each  end  a  grummet  made  of  yarn  soaked  in  red 
lead.  Before  caulking  the  joints  were  cleaned.  The  usual 
mixture  for  the  joints  was  2  pounds  of  sal-ammoniac,  i  pound 
of  sulphur  and  250  pounds  of  iron  filings  or  borings.  Air 
hammers  were  used  with  advantage  in  caulking  this  mixture 
into  the  joints. 

In  putting  in  the  concrete  lining  in  the  under-river  tunnels 
the  mixture  (proportions  i  to  2 1  to  5)  was  turned  over  for 
about  1 1  minutes  or  20  revolutions  in  No.  6  Ransome  mixers. 
A  4-bag  batch  consisted  of  one  380-lb.  barrel  of  cement,  8.75 
cubic  feet  of  sand  and  17.5  cubic  feet  of  stone.  The  average 
quantity  of  water  used  per  batch  was  25  U.S.  gallons.  Run- 
of-crusher  trap  rock  with  the  largest  stones  of  a  size  which. 


86      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

would  pass  a  2|-inch  screen  was  generally  used.  The  average 
resulting  volume  from  each  batch  was  0.808  cubic  yard.  The 
force  employed  in  mixing  concrete  per  lo-hour  shift  was  as 
follows : 

Manhattan  side: 

Foreman $3.00  per  shift 

4  men  on  sand  and  stone  cars  at  $1.75.  .  .      7.00      " 
4  men  handling  cement  at  1.75...      7.00      " 

2  men  dumping  mixers  at  1.75.  .  .     3.50      " 

Labor  per  shift $20.00 

Weehawken  side: 

Foreman $3.00  per  shift 

2  men  hauHng  cement  at  $1.75 3.50       " 

2  men  dumping  mixers  at    1.75 3.50       " 

Cost  of  labor  per  lo-hour  shift $10.00 

The  average  quantity  of  concrete  mixed  per  lo-hour  shift 
was  about  117  batches  or  90  cubic  yards.  The  maximum 
output  of  one  of  the  mixers  was  168  batches  or  129  cubic  yards 
in  a  lo-hour  shift.  The  average  force  per  shift  for  transporta- 
tion in  two  tunnels  while  building  two  arches,  two  inverts  and 
two  duct  benches  consisted  of  two  foremen,  twenty-eight 
laborers,  two  switchmen  and  four  hoisting  engineers.  The 
labor  cost  of  this  gang  was  $71  per  shift. 

The  average  time  required  to  lay  a  30-foot  length  of  invert 
was  7  hours,  but  two  spade  men  remained  for  an  hour  extra, 
smoothing  off.  The  typical  working  force  used  in  placing 
concrete  in  the  inverts  was  as  follows: 

Foreman $3.25  per  shift 

2  spaders,  $2.00 4.00 

9  laborers,  $1.75 i5-75 

Total  cost  per  shift $23.00 


NORTH   RIVER  TUNNELS  87 

The  following  force,  with  the  wages  listed,  was  used  in 
cutting  the  forms  for  the  concrete  laying: 

Foreman $4.50  per  shift 

5  carpenters,  $3.25 16.25       " 

6  carpenter's  helpers,  $2.25 i3-5o       ' ' 

Total  cost  per  shift %4-25 

The  average  time  required  to  erect  a  form  was  2  hours, 
one  carpenter  and  one  helper  remaining  until  the  concrete  was 
finished.  With  the  same  force  as  used  in  laying  the  concrete 
in  inverts  the  concrete  duct  bench  was  laid  at  a  rate  of  35  feet 
in  6  hours.  An  average  gang  for  a  20-foot  length  of  arch  was 
one  foreman,  two  spaders  and  ten  laborers,  at  a  total  labor 
cost  of  $21  per  shift. 

Two  20-foot  lengths  of  arch  were  grouted  at  one  time,  an 
average  of  three-quarters  of  a  barrel  of  cement  and  three-quarters 
of  a  barrel  of  sand  being  used  per  lineal  foot  of  tunnel.  The 
average  amount  put  in  by  one  machine  per  shift  was  15  barrels 
and  the  average  length  grouted  was  20  feet.  The  typical  work- 
ing force  on  this  work  was  as  follows: 

Foreman $3-75  per  shift 

Laborer  running  grout  machine 2.00       " 

2  laborers  handling  cement  and  sand.  .  1.75       '' 

I  laborer  tending  valves  and  pipes.  ...  1.75       " 

Total  labor  per  shift $9-25 

After  the  grouting  was  finished  the  arches  were  rubbed 
down  with  wire  brushes  to  remove  the  discoloration  and  the 
rough  places  at  the  junction  of  adjoining  lengths  were  bush 
hammered. 

The  leakage  after  the  concrete  lining  was  in  was  found  to 
be  from  0.05  to  0.06  gallon  per  lineal  foot  of  tunnel  per  24 
hours,  which  compares  favorably  with  the  records  of  other 
lined  tunnels. 

The  air  pressure  carried  during  the  progress  of  the  sub- 
river  work  varied  from  17  to  27  pounds  per  square  inch.     Behind 


88       SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

the  river  line  it  averaged  17  pounds  and  was  generally  kept 
about  equal  to  the  water  head  at  the  crown  of  the  tunnel.  Under 
the  river  the  pressure  averaged  26  pounds  per  square  inch. 
In  silt  the  pressure  was  much  lower  than  the  hydrostatic  head 
at  the  crown,  but  if  it  became  necessary  to  excavate  ahead 
of  the  shields  the  air  pressure  required  was  about  equal  to 
the  weight  of  the  overlying  material,  water  and  silt.  The  silt, 
which  weighed  from  97  to  106  pounds  per  cubic  foot,  with  an 
average  of  100  pounds,  acted  like  a  fluid.  The  compressor 
plant  was  found  to  be  ample  for  all  requirements,  except  when 
passing  the  gravel  section  at  Weehawken. 

The  quantity  of  free  air  per  man  per  hour  was  in  general 
between  1500  and  5000  cubic  feet.  When  there  was  an  excessive 
escape  through  open  gravel  the  supply  for  a  time  reached 
10,000  cubic  feet  per  hour  per  man.  For  more  than  half  of  the 
time  working  in  silt  the  supply  was  between  3000  and  4000 
cubic  feet.  But  when  it  seemed  evident  that  any  quantity 
beyond  2000  cubic  feet  had  no  beneficial  effect  on  the  health 
of  the  workers  no  attempt  was  made  to  deliver  more.  On 
two  distinct  occasions  for  two  consecutive  weeks  it  ran  as  low 
as  1000  cubic  feet  per  man  per  hour  without  any  increase  in  the 
number  of  cases  of  bends. 

The  amount  of  CO2  in  the  air  was  also  measured  daily, 
as  the  specifications  covering  the  work  called  for  not  more 
than  one  part  of  CO2  per  1000  parts  of  air.  The  average 
ranged  between  0.8  and  1.5  parts  per  1000.  In  exceptional 
cases  it  fell  as  low  as  0.3  and  rose  as  high  as  4.0.  The  temperature 
of  the  air  in  the  tunnels  usually  ranged  from  55  to  60  degrees 
Fahrenheit,  which  was  the  temperature  of  the  surrounding 
silt,  but  when  grouting  was  being  extensively  done  in  long 
sections  of  the  tunnel  in  rock,  the  temperature  varied  from 
85  to  no  degrees  Fahrenheit. 

Note. — From  paper  by  B.  H.  M.  Hewett  and  W.L.  Brown  before  the 
.American  Society  of  Civil  Engineers,  April,   19  ro. 

Various  t}^es  of  screw  piles  were  sunk  and  tests  made  not 
only  of  the  dead  load  carrying  capacity,  but  also  as  to  their 
behavior  under   the   addition   of  impact.     It  was   found   that 


NORTH   RIVER  TUNNELS  89 

screw  piles  could  be  sunk  to  hard  ground  and  would  carry  the 
required  load.  A  screw  pile  having  a  shaft  30  inches  in  diameter 
and  a  blade  5  feet  in  diameter  was  loaded  to  600,000  pounds, 
with  the  result  that  for  a  month  (the  duration  of  this  loaded 
test)  there  was  no  subsidence. 

After  the  iron  tunnel  lining  had  been  constructed  across 
the  river,  tests  were  made  of  two  types  of  support.  One  was 
a  screw  pile  29^  inches  in  diameter  with  a  blade  4  feet  8  inches 
in  diameter;  and  the  other  was  a  wrought  iron  pipe  16  inches 
in  diameter.  Tests  were  made  not  only  for  their  carrying 
capacity,  but  also  for  their  value  as  anchorages.  It  was  found 
that  the  screw  pile  was  more  satisfactory  in  every  way.  It 
could  be  put  down  much  more  rapidly,  was  more  easily  main- 
tained in  a  vertical  position,  and  as  a  support  for  the  track 
could  carry  satisfactorily  any  load  which  could  be  placed  upon 
it.  The  16-inch  pipe  did  not  prove  efticient  either  as  a  carrier 
or  as  an  anchorage. 

After  the  shields  had  met  and  the  iron  lining  had  been 
joined,  various  experiments  and  tests  were  made  in  the  tunnel. 
Screw  piles  and  the  pipes  previously  referred  to  were  inserted 
through  the  bore  segments  in  the  bottom  of  the  tunnel.  Thor- 
ough tests  were  made  with  these,  levels  were  observed  in  the 
tunnels  during  construction  and  placing  of  the  concrete  lining, 
an  examination  was  conducted  of  the  tunnels  of  the  Hudson 
and  ^Manhattan  Railroad  Company  under  traffic,  and  the  result 
was  the  decision  not  to  install  the  screw  piles.  The  tubes, 
however,  were  reinforced  longitudinally  by  twisted  steel  rods 
in  the  invert  and  roof,  and  by  transverse  rods  where  there  was 
a  superincumbent  load  on  the  tunnels  on  the  New  York  side. 
Where  they  emerge  from  the  rock  and  pass  into  soft  rock  the 
metal  shell  is  of  cast  steel  instead  of  cast  iron. 

There  was  considerable  subsidence  in  the  tunnels  during 
construction  and  lining  amounting  to  an  average  of  0.34  feet 
between  the  bulkhead  lines.  This  settlement  has  been  constantly 
decreasing  since  construction  and  appears  to  have  been  due 
almost  entirely  to  the  disturbances  of  the  surrounding  materials 
while  the  work  was  being  carried  on.     The  silt  weighs  about 


90  SUBWAYS  AND  TUNNELS   OF  NEW  YORK 

loo  pounds  per  cubic  foot  and  contains  about  38  per  cent 
water,  this  being  the  average  of  a  number  of  samples  taken 
from  the  shield  door  which  varied  in  weight  from  93  to  109 
pounds  per  cubic  foot.  It  was  found  that  whenever  this  material 
was  disturbed  outside  the  tunnels  a  displacement  of  the  tubes 
followed.  The  tubes  as  noted  have  been  lined  with  concrete 
reinforced  with  steel  rods;  and  prior  to  the  placing  of  the  con- 
crete the  joints  were  caulked,  the  bolts  grummeted  and  the 
tunnels  rendered  practically  water-tight.  The  present  quan- 
tity of  water  which  must  be  disposed  of  does  not  exceed  300 
gallons  per  twenty-four  hours  in  each  tunnel  6100  feet  long. 
The  quantities  of  some  of  the  main  items  in  the  North 
River  tunnels  are  as  follows: 

Excavation,  in  cubic  yards 238,995 

Cast  metal  used  in  tunnels,  tons 64,265 

Steel  bolts  used,  tons 3.606 

Cement  used  (concrete  and  grout)  barrels.  .  .  145,500 

Concrete,  cubic  yards 75^  4°° 

Dynamite  for  blasting,  pounds 100,400 

Brickwork,  cubic  yards 4^9^^ 

Structural  steel  (including  Pier  72),  pounds.  3,141,000 


CHAPTER   XII 

EXCAVATION  FOR  THE  TERMINAL  STATION  OF  THE  PENN- 
SYLVANIA RAILROAD 

The  site  of  the  Pennsylvania  Terminal  Station  in  New  York 
City  is  between  Tenth  and  Seventh  Avenues  and  Thirty-first 
and  Thirty- third  Streets;  it  includes  an  area  of  about  twenty- 
eight  acres. 

The  principal  contract  was  with  the  New  York  Contracting 
and  Trucking  Company,  which  was  later  assigned  by  that  com- 
pany to  the  New  York  Contracting  Company^  Pennsylvania  Ter- 
minal, for  the  performance  of  the  following  divisions  of  work. 

Excavation  for,  and  construction  of,  the  retaining  walls 
in  Seventh  Avenue  and  Thirty-first  Street,  Ninth  Avenue  and 
Thirty-third  Street;  excavation  over  the  entire  area  enclosed 
by  the  retaining  wall;  the  building  of  sewers  and  the  laying 
of  water  and  gas  mains;  the  building  of  trestles  to  support 
street  trafiic;  and  the  construction  of  the  two  twin  tunnels 
under  Ninth  Avenue. 

These  contracts  demanded  that  the  material  excavated  be 
delivered  on  board  scows  to  be  furnished  by  the  railroad  com- 
pany, alongside  the  pier  at  the  foot  of  West  Thirty-second  Street, 
North  River.  These  scows  were  supphed,  and  the  material 
was  disposed  of  from  the  pier,  by  Henry  Steers,  Incorporated, 
under  a  contract  which  called  for  the  transportation  and  placing 
of  all  material  so  delivered  in  the  Pennsylvania  Railroad  Com- 
pany's freight  terminal  at  Greenville,  N.  J. 

The  disposal  of  the  excavated  material  was  one  of  the 
principal  features  of  the  work,  and  the  above  contract  covered 
the  disposition  of  material  from  those  portions  of  the  terminal 
site  east  of  Seventh  Avenue  and  west  of  Ninth  Avenue,  from  all 
substructural  work  and  from  other  construction. 

91 


92 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


The  central  power  plant  for  conducting  this  section  of  the 
work  consisted  of  the  following  items: 

Four  Ingersoll-Rand  straight  line  air  compressors. 

One  Ingersoll-Rand  duplex  Corliss  steam  driven  compressor^ 
cross-compound,  with  a  capacity  of  5600  cubic  feet  per  minute 
compressed  to  80  pounds  at  70  r.p.m. 

Three  Ingersoll-Rand  duplex  electric-driven  air  compressors, 
driven  by  525  h.p.,  6600  volt  General  Electric  motors,  with  a 


Ingersoll-Rand  Rock  Drills  in  P.  R.  R.  Terminal  Excavation. 
capacity  of  3000  cubic  feet  per  minute,  compressed  to  80  pounds 
at  125  r.p.m. 

Two  10-  by  6-  by  lo-inch  Worthington  steam  pumps. 

One  7 J  h.p.  General  Electric  motor,  driving  the  coal  conveyor. 

One  8-  by  lo-inch  Buffalo  Forge  Go's  engine  driving  the 
forced  draft  fan. 

Three  500  h.p.  Stirhng  water  tube  boilers. 

In  the  repair  shop  attached  to  this  work,  were  two  large 
Ajax  drill  sharpeners  which  took  care  of  the  steels  from  the 
rock  drills  in  the  excavation. 


EXCAVATIOX   FOK   THE  TERMINAL  STATION 


93 


In  the  pit  excavation  equipment  the  following  items  were 
included: 

Three  70-ton  Bucyrus  steam  shovels. 

Two  30-ton  steam  shovels  (Marion  and  Ohio). 

Eighty  Ingersoll-Rand  rock  drills. 

Two  Ingersoll-Rand  quarry  bars. 

Twenty-one  10-  by  16-inch,  36-inch  gage  Porter  locomotives. 

Three  9-  by  16-inch,  36-inch  gage  Davenport  locomotives. 


^Subgnde  282.40 


TERMINAL  STATION  WEST 

TYPICAL   SECTIONS 


Cross-Sections  of  P.  R.  R.  Terminal  Excavation. 

One  hundred  and  forty  four-yard  Western  dump  cars. 

One  hundred  and  sixty-five  fiat  cars  with  four-yard  iron  skips. 

The  machine  equipment  at  the  dock  included  six  stiff-leg 
derricks  with  35-foot  masts  and  40-foot  booms  operated  by 
60  h.p.  three-drum  Lambert  hoisting  engines  with  Northern 
motors,  and  eight  Dodge  electric  telphers  with  General  Electric 
motors. 

Ground  was  broken  under  the  principal  contract  July  9, 
1904.  Two  methods  wTre  used  in  making  the  excavation  for  the 
retaining  walls  and  in  building  these  walls;  construction  in  the 
trench,  and  construction  on  the  bench.  In  general,  the  trench 
method  was  used  wherever  the  rock  on  which  the  wall  was  to  be 


94      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

built  was  twelve  feet  or  more  below  the  surface  of  the  street  or 
where  the  buildings  adjoining  the  wall  were  not  founded  on  rock. 

In  the  trench  method  the  base  of  the  wall  was  staked  out 
on  the  ground  surface  and  as  much  width  was  added  as  was 
needed  for  sheeting  and  working  space.  All  of  this  was  then 
excavated  to  a  depth  of  5  feet  before  timbering  was  begun. 
A  cable-way  was  erected  and  the  spoil  placed  in  buckets  and 
dumped  into  wagons.  Some  very  difficult  material  was  encoun- 
tered in  the  deeper  excavations;  beds  of  quicksand  were  passed 
through  varying  from  i  to  18  feet  in  thickness. 

After  encountering  a  fine  sand  in  one  trench  no  headway 
was  made  until  a  tight  wooden  cylinder  was  sunk  through  the 
sand  by  excavating  the  material  inside  of  it  and  heavily  weighting 
the  shell  with  pig  iron.  When  this  cylinder  had  reached  the 
gravel  which  lay  below  the  sand,  it  was  used  as  a  sump,  and  the 
water  level  kept  below  the  excavation,  which  permitted  good 
progress.  Sand  continued  to  flow  under  the  sheeting  to  such 
an  extent  that  the  front  walls  of  four  adjoining  buildings  were 
badly  cracked  and  had  to  be  rebuilt. 

The  bench  method  of  excavation  for  the  retaining  wall  was  sim- 
ple, and  was  used  only  when  the  rock  lay  near  the  surface  and  when 
the  adjoining  buildings  had  a  rock  foundation.  As  the  overlying 
material  w^as  dry  and  firm,  little  or  no  shoring  was  required. 

The  concrete  retaining  walls  were  usually  built  in  sections 
50  feet  long.  The  trenches  were  not  allowed  to  be  opened  for 
the  full  depih.  Concreting  was  started  as  soon  after  the 
necessary  length  of  rock  had  been  uncovered  as  the  forms  and 
preliminary  work  for  a  section  could  be  prepared.  Generally 
each  section  was  a  monolith.  The  concrete  was  mixed  by 
power  in  the  proportions  of  i  part  of  cement,  3  parts  of  sand, 
and  5  parts  of  stone.  Facing  mortar  2  inches  thick  was  deposited 
at  the  same  time  as  the  concreting,  being  separated  from  the 
latter  by  a  steel  diaphragm  until  both  were  in  place.  The 
diaphragm  was  then  removed  and  the  two  spaded  together. 
The  layers  of  concrete  never  exceeded  8  inches  in  thickness. 

After  a  section  of  the  concrete  wall  had  firmly  set,  both 
back  and  front  forms  were  removed  and  the  thrust  from  the 


EXCAVATION  FOR  THE  TERMINAL  STATION 


95 


-EUi.Top  of  Curb.  31 ««  St 


EleT.Top  of  Curb,  31«t  St. 


262.-'to  Left  Cen.LlDe  TonnlnfcLjX 
KIa'u)  Right il. 


O — 0  Gia 
0--12'w«t«t 


TYPICAL  SECTIONS 

OF  RETAINING  WALL 

IN  THIRTY-FIRST  STREET 


Retaining  Walls  for  P.  R.  R.  Terminal  Excavation. 


96      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

sides  of  the  trench  transferred  directly  to  the  finished  wall. 
The  face  of  the  wall  was  rubbed  with  a  cement  brick  to  remove 
the  marks  of  the  planks,  and  washed  with  a  thin  cement  grout. 

Waterproofing  and  brick  armor  were  then  continued  up  the 
back  of  the  wall,  the  waterproofing  consisting  of  three  layers  of 
"  Hydrex  "  felt  and  four  layers  of  coal-tar  pitch.  The  pitch  con- 
tained not  less  than  25  per  cent  of  carbon,  softened  at  60  degrees 
Fahrenheit  and  melted  at  between  96  and  106  degrees  Fahrenheit. 

In  designing  the  concrete  wall  the  following  were  assumed: 

Weight  of  concrete,  140  pounds  per  cubic  foot. 

Weight  of  material  from  the  ground  surface  to  the  depth  of  12 
feet,  100  pounds  per  cubic  foot;  and  the  angle  of  repose  30  degrees. 

The  weight  of  buildings  back  of  the  wall  was  neglected,  as 
it  was  assumed  to  be  about  equal  to  that  of  the  cellars  filled  with 
material  w^eighing  100  pounds  per  cubic  foot. 

Reaction  from  superstructure,  live  and  dead  load,  20,000 
pounds  per  lineal  foot  of  wall. 

Weight  of  materials  below  the  12-foot  depth  line,  124  pounds 
per  cubic  foot. 

The  resultant  of  both  horizontal  and  vertical  forces  should, 
at  all  points,  fall  within  the  middle  third  of  the  wall;  in  other 
words,  there  should  be  no  tension  in  the  concrete. 

While  the  pit  excavation  was  started  by  hand,  three  70-ton 
steam  shovels  were  put  to  work  as  soon  as  they  could  be  delivered. 
The  excavated  material  was  loaded  by  the  shovels  into  2-yard 
end-dump  wagons  and  conveyed  to  the  dumping  board  at 
Thirty-fifth  Street. 

The  average  number  of  teams  employed  was  140.  10  per 
cent  of  which  were  snatch  teams  to  pull  the  wagons  out  of  the 
pit,  and  to  assist  them  up  the  runway  at  the  dumping  board. 
The  teams  averaged  only  seven  trips  per  day  of  ten  hours. 
The  number  of  teams  was  not  sufficient  to  keep  the  three  shovels 
busy  when  in  good  digging;  but  the  dumping  board  was  taxed 
to  the  limit  of  its  capacity. 

As  the  shovels  had  three-and-one-half-yard  buckets,  one 
bucketful  meant  a  wagon  full  and  running  over.  The  output 
from  August   to   November   inclusive   averaged   40,000   cubic 


EXCAVATION   FOR  THE   TERMINAL  STATION  97 

yards  per  month.  One  shift  only  was  worked  per  day.  The 
quantity  was  not  large  for  such  shovels  to  dig,  but  it  was  a  large 
quantity  to  truck  through  the  streets  and  required  the  passage, 
at  a  given  point,  of  one  team  every  i8  seconds. 

At  the  beginning  of  the  team  transportation  period,  on  May 
22,  1905,  two  shifts  of  ten  hours  each  were  inaugurated,  and 
the  earth  was  handled  at  the  rate  of  85,000  to  90,000  cubic 
yards  per  month.  But  by  the  end  of  August,  when  a  little 
more  than  60  per  cent  of  the  total  earth  had  been  disposed  of, 
the  rock  began  to  interfere  with  the  progress.  The  strike  of 
the  rock  was  almost  directly  north  and  south,  and  its  surface 
formed  broken  ridges  in  that  direction  with  deep  valleys  between. 
The  dip  was  almost  vertical  near  Ninth  Avenue  and  about 
70  degrees  toward  the  west  near  Seventh  Avenue.  This  made 
it  necessary  to  turn  the  shovels  parallel  to  the  ridges  in  order 
to  strip  the  rock  for  drilling.  As  the  ridges  were  very  much 
broken  the  shovels  continued  to  bump  into  them  on  all  occassions, 
making  it  necessary  to  move  back  and  start  other  cuts,  or 
stand  and  wait  for  the  rock  to  be  drilled  and  blasted. 

A  small  Vulcan  steam  shovel  with  a  three-quarter-yard 
dipper  was  brought  on  the  work  to  do  the  stripping.  It  was 
moved  so  readily  from  place  to  place  that  another  shovel  of 
smaller  t>pe  was  put  in  use  and  thereafter  the  stripping  was 
done  largely  by  these  two  small  shovels  and  by  hand.  The  large 
shovels  were  used  almost  exclusively  in  handling  rock. 

The  drilling  necessary  to  remove  the  rock  was  very  large 
in  total  amount  and  also  in  amount  per  yard  excavated.  In 
order  not  to  damage  the  retaining  walls  and  the  rock  underl}-ing 
them,  holes  spaced  at  five-inch  centers  were  drilled  i  foot  away 
from  the  face  of  the  holes  and  on  the  same  batter.  These 
breaking  holes  alone  amounted  to  a  total  of  210,000  Hneal  feet 
or  I  foot  of  hole  for  each  33  cubic  yard  of  rock  excavated.  The 
regulations  of  the  Bureau  of  Combustibles  which  prohibit 
springing  of  holes  compelled  the  placing  of  drilled  holes  very 
close  together,  making  a  total  of  about  420,000  Hneal  feet  which, 
added  to  the  other  210,000  lineal  feet,  brings  the  aggregate 
to  630,000  feet.     If  to  this  is  added  the  block  holes  (for  some 


98      SUBWAYS  AND  TUNNELS  OF  NEW  YROK 

of  the  rock  broke  large)  it  will  show  at  least  i  foot  of  hole  drilled 
for  each  cubic  yard  of  rock  excavated. 

The  excavated  material  was  hauled  from  the  shovels  to  the 
pier  in  lo-car  trains.  The  cars  were  of  three  classes,  namely, 
4-yard  dump  cars,  fiat  cars  and  fiat  cars  carrying  4-yard 
skips.  So  far  as  practicable,  earth  and  rocks  of  one  cubic 
yard  or  less  were  loaded  in  the  dump  cars;  larger  rocks  on  the 
flat  cars;  and  medium  sized  rocks  in  the  skips.  The  dump 
cars  were  run  at  once  to  the  hoppers,  dumped  and  returned 
to  the  pit;  the  fiat  cars  and  skips  were  run  under  the  derricks 
and  telphers  and  the  large  rocks  unloaded,  after  which  they 
were  run  to  the  hoppers  and  emptied. 

The  total  quantity  of  excavated  material  handled  on  this 
pier  from  May  22,  1905  to  December  31,  1908  amounted  to 
673,800  cubic  yards  of  earth  and  1,488,000  cubic  yards  of  rock, 
place  measurement.  This  is  equal  to  3,208,400,  cubic  yards, 
scow  measurement.  In  addition  to  this,  175,000  cubic  yards 
of  crushed  stone  and  sand,  and  6000  car  loads  of  miscellaneous 
building  materials  were  transferred  from  scows  and  lighters 
to  smaller  cars  for  delivery  to  the  Terminal  work. 

All  the  earth  and  570,000  cubic  yards  of  rock,  place  measure- 
ment, were  handled  from  the  chutes.  The  remainder  of  the  rock, 
amounting  to  918,000  cubic  yards,  and  all  the  incoming  material 
were  handled  by  the  derricks  and  telphers.  In  materials- 
handling  capacity  one  telpher  was  about  equivalent  to  one 
derrick.  A  train,  therefore,  could  be  emptied  or  a  boat  loaded 
under  the  bank  of  eight  telphers  in  one-quarter  of  the  time 
required  by  the  derricks,  of  which  two  only  could  work  on  one 
boat.  The  telphers  were  of  great  advantage  where  track  room 
and  scow  berths  were  Hmited. 

The  material  from  various  contracts  of  the  Pennsylvania 
Railroad  extension,  which  was  transported  and  disposed  of 
by  Henry  Steers,  Incorporated,  amounted  to  4,457,800  cubic 
yards.  Of  this,  3,454,800  cubic  yards  were  placed  in  the  freight 
terminal  yard  at  Greenville,  N.  J.;  711,900  cubic  yards  in  the 
Meadows  division;  and  291,000  cubic  yards  at  other  points. 
Handling  this  material  required  the  loading  of  from  ten  to  twenty 


EXCAVATION   FOR  THE  TERMINAL   STATION 


99 


scows  per  day.  The  average  for  more  than  two  years  was 
fourteen  per  day.  As  the  average  time  spent  in  one  round  trip 
was  three  and  one-third  days,  a  fleet  of  more  than  fifty  scows 
was  required  to  keep  all  points  supplied.  All  loaded  scows 
were  towed  from    the  docks    to    stake  boats    about  one  mile 


Drilling  for  P.  R.  R.  Terminal  Flxcavation. 

ofT  shore  at  Greenville.  From  there  they  were  taken  to  the 
different  unloading  points  by  smaller  tugs  which  also  returned 
the  empty  scows  to  the  stake. 

The  unloading  plants  were  similar  at  the  difTerent  points, 
although  that  at  Greenville  was  much  larger  than  the  others. 
It  included  five  land  dredges  and  eight  traveling  derricks  of  two 


100      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

types,  one  floating  and  the  other  mounted  on  wheels  and  traveling 
on  a  track  of  i6-ft  gage.  The  derricks,  which  were  of  the 
"  A  "  frame  type  and  capable  of  handling  20  tons,  were  used 
for  the  larger  rocks  which  were  deposited  by  the  derricks  either 
in  the  channels  along  which  they  worked  or  in  the  fill  along 
shore,  without  the  use  of  cars.  The  land  dredges  had  60-foot 
booms,  carrying  two-and-one-half-yard  Hayward  buckets 
operated  by  a  14-  by  18-inch  double-drum  dredging  engine.  They 
loaded  into  9-yard,  standard  gage,  side  dump  cars,  built  by 
the  contractor;  and  unloaded  the  scows  to  within  one  foot 
of  the  deck.  The  material  remaining  was  loaded  by  hand  into 
skips  which  were  dumped  into  the  cars  by  small  derricks,  one 
of  which  was  located  at  the  rear  of  each  dredge.  The  cars  were 
hauled  to  the  dump  by  25-ton  standard  gage  locomotives. 

The  cost  of  repairs  to  the  scows,  due  to  loading,  transporta- 
tion and  unloading  at  all  points,  was  about  three  and  one-half 
cents  per  cubic  yard.  In  addition  it  cost  four-tenths  of  a  cent 
per  cubic  yard  for  scows  overturned  or  sunk  in  servic^^^^aking 
three  and  nine-tenths  cents  in  all.  ^^^^^LcrT^.a.^^u^^ 

The  two  double-track  tunnels  under  Ninth  Avenue,  w^ch  were 
constructed  to  obtain  100  feet  of  additional  tail  room  on  each  of 
the  four  tracks,  required  an  excavation  75  feet  wide.  The  rock 
was  of  fair  quality,  but  not  firm  enough  to  support  so  great  a  span 
in  a  single  tunnel.  To  obviate  the  necessity  of  timbering,  the 
center  wall  was  built  before  excavating  for  the  full  width.  The 
dip  of  the  rock  at  this  point  is  almost  90  degrees.  To  prevent 
blowing  away  the  entire  face  in  excavating  for  the  tunnel,  the  pit 
excavation  was  not  carried  west  to  the  final  face  below  the 
springing  line,  but  a  lo-foot  bench  was  left  at  that  elevation. 

A  top  heading  9  by  9  feet  in  section  was  started  above  the 
bench,  and  when  10  feet  had  been  penetrated  it  was  widened 
to  20  feet.  A  cross-heading  was  driven  in  each  direction  at  the 
west  end  of  the  first  heading.  The  bench  was  then  shut  down 
and  the  first  10  feet  of  longitudinal  heading  was  widened  suf- 
ficiently to  receive  the  center  wall. 

When  the  middle  wall  had  been  concreted  all  voids  between 
the  top  and  the  rock  were  grouted  through  pipes  left  for  the 


EXCAVATION   FOR  THE  TERMINAL   STATION 


101 


purpose.  The  wall  was  then  protected  by  curtains  of  heavy 
round  timber  securely  wired  together  and  the  remainder  of  the 
excavation  was  made  by  widening  the  cross-headings  toward 
the  face.  The  muck  was  carried  out  by  cableways,  one  on  each 
side  of  the  completed  wall.  Each  cableway  was  supported  by 
a  tower  outside  the  tunnel  and  by  a  large  hook-bolt  grouted 
into  the  rock  at  the  inner  end  of  the  tunnel.  Forms  were  built 
for  each  tunnel  complete,  and  the  concrete  was  delivered  by  a 


Looking  east  at  Seventh  Avenue.  Approach  to  new  Pennsylvania  Terminal, 
with  Cameron  Pump  removing  400  gallons  drainage  water  per  minute 
from  the  diggings  to  the  sewer  65  feet  above. 

belt  conveyor,  running  over  the  top  of  the  lagging  and  moved 
out  as  the  tunnel  was  keyed.* 

The  rock  formation  consisted  of  quartz,  feldspar  and  mica, 
with  some  hornblende,  serpentine,  pyrites  and  tourmaline. 
The  formation  varied  from  mica  schist  to  granite  and  may  be 
generally  classed  as  gneiss.     The  total  rock  excavation  with  an 

*From  a  paper  by  George  C.  Clark,  M.A.S.C.E.,  on  The  New  York  Tunnel 
Extension  of  the  Pennsylvania  Railroad  and  The  Site  of  the  Terminal  Station, 
in  the  Proceedings  of  the  .\.S.C.E.,  March,  1910. 


102 


SUBWAYS  AND  TUNNELS   OF  NEW   YORK 


c  f2 


EXCAVATION   FOR  THE  TERMINAL  STATION  103 

average  depth  of  50  feet  was  about  450,000  cubic  yards  in 
open  cut.  The  general  method  of  drilling  for  the  different 
classes  of  work  was  as  follows : 

In  breaking  down,  the  holes  were  started  about  8  feet  apart, 
on  a  slight  batter,  so  that  at  the  bottom  they  would  be  less 
than  8  feet  apart.  They  were  drilled  10  feet  deep,  and  it  was 
necessary  to  load  heavily  to  lift  the  cut.  When  a  side  cut 
of  about  20  feet  had  been  made,  the  side  holes  were  drilled  20 
feet  deep  and  the  holes  loaded  and  tamped  for  the  full  20-foot 
cut.  The  terms  of  the  specifications  required  the  contractor 
to  finish  the  sides  of  the  excavation  by  broaching  holes. 

For  the  steam  shovel  excavation,  on  portions  of  the  work 
spring  holes  were  used.  These  holes  were  20  feet  deep.  Two 
or  three  sticks  of  dynamite  were  exploded  at  the  bottom  of  the 
holes,  and  no  tamping  was  used.  This  process  was  repeated 
with  increasingly  heavy  charges  until  a  cavity  was  formed  of  a 
size  which  would  hold  from  100  to  200  pounds  of  dynamite. 
Face  and  breast  holes  were  drilled,  and  by  this  means  cuts  20 
feet  by  15  feet  thick  were  broken  up. 

The  average  performance  from  more  than  25,000  drill  shifts 
showed  ^T,  lineal  feet  of  hole  per  8-hour  shift.  The  average 
cubic  yards  per  drill  shift  was  13.9.  The  average  driUing  per 
cubic  yard  was  2.4  feet.  The  dynamite  used  was  60  per  cent, 
and  the  average  excavation  per  pound  of  dynamite  was  2.2 
cubic  yards.  The  average  performance  of  derricks,  with  gangs 
of  twelve  men  and  one  foreman,  was  50  cubic  yards  per  8-hour 
shift.  The  cost  of  field  engineering  and  office  was  2.8  per  cent  of 
the  cost  of  work  executed,  of  which  2.7  per  cent  was  for  salaries. 

The  quantities  of  some  of  the  main  items  in  the  excavation 
of  the  Terminal  Station  are  as  follows: 

Excavation,  in  cubic  yards 517,000 

Cement  used  (concrete  and  grout),  barrels  33.000 

Concrete,  cubic  yards 18.500 

Dynamite  for  blasting,  pounds 206,000 

Structural  Steel  (including  Pier  72),  pounds  1,475,000 

*  From  a  paper  by  B.  F.  Cresson,  Jr..  before  ihe  A.S.C.E.,  .April  6,  1910. 


CHAPTER  XIII 

CROSS-TOWN  TUNNELS   OF  THE   PENNSYLVANIA   RAILROAD 

On  May  29,  1905,  a  contract  was  entered  into  with  the 
United  Engineering  and  Contracting  Company  for  the  construc- 
tion of  the  tunnels  for  the  Pennsylvania  Railroad  extending 
eastward  from  the  easterly  extension  of  the  Terminal  Station 
in  New  York  City  to  the  permanent  shafts  just  east  of  First 
Avenue,  where  they  connected  with  the  East  River  tunnels. 

These  cross-town  tunnels  are  located  under  Thirty-second 
and  Thirty- third  streets,  from  the  Terminal  Station  to  Second 
Avenue.  Curving  thence  to  the  left,  they  pass  under  private 
property  and  under  First  Avenue  to  the  shafts. 

The  method  of  handling  the  work  adopted  by  the  contractor 
was  in  general  as  follows:  Excavation  was  carried  on  by 
modifications  of  the  top-heading  and  bench  method,  the  bench 
being  carried  as  close  to  the  face  as  possible  in  order  to  allow 
the  muck  from  the  heading  to  be  thrown  by  the  blast  over  the 
bench  into  the  full  tunnel  section.  The  spoil  was  loaded  into 
3-yard  buckets  of  a  special  design  by  means  of  Marion  steam 
shovels  operated  by  compressed  air;  and  these  buckets  were 
hauled  to  the  shafts  by  General  Electric  electric  locomotives. 

Electrically  operated  telphers  suspended  from  a  timber 
trestle  hoisted  the  buckets  and,  traveling  on  a  mono-rail  track, 
deposited  them  on  wagons  for  transportation  to  the  dock. 
At  the  dock  the  buckets  were  lifted  by  electrically  operated 
stiff-leg  derricks  and  the  contents  deposited  on  scows  for  final 
disposal.  The  spoil  was  thus  transported  from  the  heading  to 
the  scow  without  breaking  the  bulk.  When  the  concreting 
was  in  progress  the  spoil  buckets  were  returned  to  the  shafts 
loaded  with  stone  and  sand. 

104 


i    Top  cf  TU  :  i; 


t/IBERI 


k 


Ss^ 


u^ 


is::^^_^_— n  _ 


JUNCTION  OF  SHIELD  CHAMB 


UNCTION   19  6  AND  24  6  SPANS 


-VlHft-|  /  / 


,„"'i::.'."if,'^'-         Vii'S  '?    -2 


ig'o'gpim  TvrlD  Tunnels, 


\  , 


I9'0"SPAN  TWIN  TUNNELS.  ELLIPTICAL  ARCHES 

Typifiil  Cro&s-Sections,  Ponnsylvnnin  R.R.  Cross-TowTi  TimnelB. 


;  I  TYPICAL    SECTIONS 

\  THIRTY-SECOND  STREET  TUNNELS 

!"  SHIELD  CHAMBERS,  ETC. 


u'^'Spmi  Twin  Tunnel^  Open  Cut 


CROSS-TOWN  TUNNELS  105 

The  power  house  at  the  corner  of  Thirty-first  Street  and 
Fourth  Avenue  supplied  compressed  air  for  operating  the 
drills,  shovels,  pumps  and  hoists  in  the  tunnel  driven  from  the 
river  shafts.  It  included  three  Laidlaw-Dunn-Gordon  com- 
pressors. The  largest  was  a  2-stage,  cross-compound,  direct- 
connected,  electric  unit,  32  and  20  by  30  inches,  driven  at  100 
r.p.m.  by  a  480  h.p.,  230- volt,  direct  current  Fort  Wayne 
constant  speed  motor.  This  unit  was  rated  at  2870  cubic 
feet  of  free  air  per  minute  at  a  pressure  of  100  pounds.  It  was 
governed  by  throttling  the  suction,  the  governor  being  con- 
trolled by  the  pressure  in  the  air  receiver  and  the  motor  running 
continuously  at  regular  speed.  The  two  other  compressors 
were  of  smaller  type;  one  22^  and  14  by  18  inches,  rated  at 
1250  cubic  feet  of  free  air  per  minute  at  100  pounds  pressure; 
the  other  16  and  10  by  18  inches,  rated  at  630  cubic  feet  per 
minute.  They  were  driven  at  150  r.p.m.  by  105  h.p.,  220- 
volt,  direct  current  General  Electric  motors,  having  a  speed  of 
655  r.p.m.  The  larger  of  these  two  compressors  was  driven 
by  two  of  the  motors  belted  in  tandem,  and  the  smaller  was 
belt-connected  to  a  third  motor.  All  of  these  compressors 
were  water-jacketed  and  fitted  with  intercoolers,  the  water 
supply  for  cooling  purposes  being  furnished  by  a  water  cooHng 
tower. 

The  Dodge  telphers  used  for  hoisting  muck  from  the  tunnels 
and  for  lowering  supplies,  were  hung  from  single  rails  on  a 
timber  trestle  about  40  feet  high  spanning  and  connecting 
the  two  shafts.  They  were  operated  by  a  75-h.p.  General 
Electric  motor  for  hoisting,  and  a  15-h.p.  Northern  motor 
for  propelhng.  Their  rated  lifting  capacity  was  10,000  pounds, 
at  a  speed  of  200  feet  per  minute. 

During  excavation  the  headings  were  supplied  with  forced 
ventilation  from  12-  and  14-inch  Root  spiral  riveted  asphalted 
pressure  pipes.  Canvas  extensions  were  used  beyond  the  ends 
of  the  pipes  and  air  was  supplied  by  a  blower  driven  by  a 
15-h.p.  motor. 

The  air  compressing  plant  for  the  intermediate  shaft  was 
located  at  the  rear  of  the  Thirty-third  Street  shaft  and  supplied 


106      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

air  for  driving  the  tunnels  east  and  west  from  the  shafts,  both 
under  Thirty-second  and  Thirty-third  Streets.  Two  Laidlaw- 
Dunn-Gordon  compressors,  similar  to  the  larger  machine  in 
the  First  Avenue  plant,  were  here  installed,  with  a  similar 
water  coohng  tower.  The  equipment  also  included  American 
blowers  with   General  Electric  motors  for  forced  ventilation. 

For  the  receipt  and  disposal  of  materials  at  the  Thirty- 
fifth  Street  pier,  there  was  an  equipment  of  four  stiff-leg  der- 
ricks operated  by  Lidgerwood  and  Lambert  electric  hoists. 
Two  -were  used  in  lifting  the  muck  buckets  from  the  wagons 
and  dumping  them  on  the  scows  for  final  removal.  The  other 
two  were  fitted  with  clam-shell  buckets  for  unloading  sand  and 
broken  stone  from  the  barges  and  for  depositing  the  materials 
in  large  hoppers  from  which  the}'  were  drawn  into  wagons  for 
transportation  to  the  various  concrete  plants. 

In  the  tunnels  the  loading  was  done  with  air  operated  steam 
shovels.  Four  of  these,  Marion  Model  20,  were  used  at  various 
points  of  the  work.  The  material  was  carried  from  the  shafts 
in  buckets  of  special  design.  The  buckets  were  carried  in 
the  tunnel  on  flat  cars  and  through  the  streets  on  wagons, 
both  cars  and  wagons  being  provided  with  cradles  shaped 
to  receive  them.  The  tunnel  cars  were  hauled  by  standard 
ID- ton  General  Electric  electric  mine  locomotives,  the  current 
for  which  was  taken  at  220  volts  from  a  pair  of  trolley  wires 
suspended  from  the  roof  of  the  tunnel.  Two  eight-and-one- 
half-ton  Davenport  steam  locomotives  were  also  used  toward 
the  end  of  the  work.  The  steam  shovels  were  supplemented 
by  two  15-ton  Browning  locomotive  cranes  which  handled  the 
spoil  in  places  where  the  timbering  interfered  with  the 
operation  of  the  shovels.  All  tracks  were  of  3-foot  gage  and 
laid  with  40-pound  rail. 

Practically  all  of  the  heavy  drilling  was  done  with  Ingersoll- 
Rand  '^  E-52  "  rock  drills,  the  trimming  being  done  with 
"  Little  Jap  "  and  "  Baby  "  drills.  A  large  number  of  pumps 
were  used  at  various  points  of  the  work,  practically  all  of  them 
being  of  Cameron  make.  The  grout  machines  were  of  the 
vertical  cylinder,  air  stirring  t\7)e. 


CROSS-TOWX  TUNNELS  107 

The  sinking  of  the  intermediate  shafts  was  the  first  work 
undertaken.  The  shaft  at  Thirty-third  Street  had  a  cross- 
section  of  34^  feet  by  21  feet,  and  was  83  feet  deep.  The 
rock  surface  averaged  5  feet  below  the  ground  surface.  Sinking 
was  started  on  July  10,  1905,  and  was  completed  on  October  3d 
of  the  same  year,  the  rock  throughout  being  hard  and  dry. 
The  average  daily  rate  of  sinking  was  0.73  feet  and  an  average 
of  1 7. 1  cubic  yards  was  excavated  per  day  with  two  shifts  of 
eight  hours  each.  The  first  shift  was  started  at  6  a.m.,  and  the 
second  at  2 :30  p.m.,  ending  at  1 1  p.m.  These  hours  were  adopted 
to  avoid  undue  disturbances  during  the  night. 

Before  blasting  the  first  lift  of  rock,  channel  cuts  5  or  6  feet 
deep  were  made  along  the  sides  of  the  shaft  in  order  to  avoid 
damage  to  the  walls  of  the  neighboring  buildings.  Timber- 
ing was  required  for  a  depth  of  only  10  feet  below  the  surface 
of  the  ground.  A  drift  30  feet  long,  17  feet  wide  and  27  feet 
high  connected  the  south  end  of  the  shaft  with  the  tunnels. 
This  drift  was  excavated  in  three  stages,  a  top  heading  and 
a  bench  in  two  lifts.  While  blasting  the  cut  in  the  top  heading, 
concussion  was  sufiEicient  to  break  glass  in  the  neighboring 
buildings.  The  use  of  a  "  Radialaxe  "  machine  for  making 
a  cut  to  blast  on  open  ends  reduced  this  concussion. 

The  construction  of  the  Thirty-second  Street  shaft  was 
similar  to  that  at  Thirty-third  Street,  this  shaft  being  31 J  by 
2o4  feet  in  section,  with  a  depth  of  71  feet.  The  depth  of 
earth  excavation  averaged  19^  feet.  Sinking  was  started 
May  15,  1905,  and  completed  on  the  26th  of  the  following 
October.  The  daily  average  rate  was  0.3  feet  in  earth  and  0.52 
feet  in  rock.  The  drift  from  shaft  to  tunnel  was  excavated 
in  much  the  same  manner  as  the  one  at  Thirty-third  Street. 

For  an  average  distance  of  350  feet  from  the  First  Avenue 
shafts  there  were  four  single-track  tunnels.  The  rock  was 
sound  and  dry.  A  top  heading  of  the  full  size  of  the  tunnel 
and  about  8  feet  high  was  first  driven,  drilling  being  done  by 
four  drills  mounted  on  two  columns  and  the  holes  blasted  in 
the  ordinary  way.  The  bench  was  13  feet  high.  Drills  on 
tripods  were  used  on  the  bench,  but  owing  to  the  lack  of  head- 


108      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

room,  steels  long  enough  to  reach  the  bottom  of  the  bench 
could  not  be  used.  Drills  on  tripods  were  placed  as  low  as 
possible  and  lift  holes  were  drilled  1 5  degrees  from  the  horizontal 
at  the  bottom  of  the  bench.  Headings  were  driven  ic  to  20 
feet  in  advance  of  the  bench.  In  these  single  tunnels  the  muck 
was  loaded  by  hand. 

From  the  end  of  the  single-track  tunnel  westward  to  Fifth 
Avenue  on  Thirty-third  Street  and  to  Madison  Avenue  on 
Thirty-second  Street  (with  some  exceptions)  each  pair  of  tunnels 
was  excavated  for  the  entire  width  at  one  operation.  Three 
distinct  methods  were  extensively  used.  The  double  heading, 
the  center  heading  and  the  full-sized  heading  method.  These 
differed  only  in  the  manner  of  blasting  and  drilling.  The 
bench  was  usually  within  10  or  15  feet  of  the  face  and  was 
drilled  and  fired  in  the  same  way  as  in  the  single  tunnels. 

In  the  double  heading  method  the  top  headings  for  each 
tunnel  were  driven  separately,  leaving  a  short  rock  core  wall 
between  them.  These  headings  were  drilled  from  columns 
in  the  same  manner  as  in  the  single  tunnels.  The  temporary 
dividing  rock  wall  between  the  headings  was  drilled  by  a  tripod 
drill  on  the  bench  of  one  of  the  headings,  and  was  fired  with 
the  bench. 

In  the  center  heading  method  only  one  heading  was  driven, 
rectangular  in  shape  and  about  8  feet  high  by  14  feet  wide. 
It  was  on  the  center  line  between  the  tunnels.  In  general, 
the  face  was  from  6  to  1 2  feet  (the  length  of  one  or  two  rounds) 
in  advance  of  the  face  at  the  top.  The  center  heading  was 
drilled  by  four  drills  mounted  on  two  columns.  By  turning 
these  drills  to  the  side  they  were  used  for  holes  at  right  angles 
to  the  line  of  the  tunnel;  and  by  means  of  these  latter  holes 
the  remainder  of  the  face  of  the  heading  was  blasted.  By 
turning  the  drills  downward  the  bench  holes  under  the  center 
heading  were  also  drilled. 

Where  the  full  heading  method  was  employed  ten  drills 
were  mounted  on  five  columns  across  the  face.  Holes  were 
drilled  to  form  a  cut  near  the  center  line  between  the  tunnels. 
The  remainder  of  the  holes  were  located  so  that  they  would 


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Methods  of  Excavation  and  Timbering,  Pennsylvania  R.R.  Cross-Town  Tunnels. 


CROSS-TOWN   TUNNELS 


109 


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Construction   of   twin   tunnels    through    excavation    started    for    three-track 
tunnel  in  Thirty-third  Street  near  Fifth  Avenue. 


no      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

draw  into  the  center  of  the  cut.  The  bench  was  frequently 
drilled  from  the  same  set-up  of  columns  by  turning  the  drills 
downward.  In  sound  rock  this  method  proved  to  be  the  most 
rapid  of  the  three. 

Practically  all  trimming  was  left  until  immediately  before 
the  concreting  was  begun.  It  was  then  taken  up  as  a  separate 
operation,  but  proved  to  be  costly  and  tedious,  and  a  hindrance 
to  the  placing  of  the  Uning.  The  rock  encountered  was  Hudson 
schist,  varying  widely  in  character. 

The  material  excavated  from  the  tunnels  was  dumped  on 
barges  at  the  Thirty-fifth  Street  pier.  These  barges  were 
towed  to  points  near  the  Bayonne  Peninsula  where  the  spoil 
was  used  principally  in  the  construction  of  the  Greenville  freight 
terminal.  A  portion  was  also  used  in  building  the  extension 
across  the  Hackensack  meadows  to  the  Bergen  Hill  tunnel. 
The  average  rate  of  advance  in  the  full-sized  tunnels  was  from 
3.8  to  4.7.  feet  per  day,  in  the   full-sized   twin  tunnels,  from 

1.4  to  5.8.  feet  per  day,  and  in  exploration  drifts  from  4.6  to 

6.5  feet  per  day. 

From  a  paper  by  James  H.  Brace  and  Francis  Mason,  in  the  Proceedings  of 
the  A.S.C.E.  for  October,  1909. 


CHAPTER   XIV 

THE  EAST  RIVER  TUNNELS  OF  THE  PENNSYLVANIA  RAILROAD 

From  the  inception  of  the  Pennsylvania  Railroad  project 
it  was  recognized  that  the  most  difficult  and  expensive  section 
of  the  work  would  be  the  tunnels  under  the  East  River  from 
Manhattan  Island  to  Long  Island.  The  borings  along  the 
line  of  the  tunnel  in  the  river  bed  had  shown  a  great  variety 
of  materials  to  be  passed  through,  comprising  quicksand, 
coarse  sand,  gravel,  boulders  and  bed  rock,  as  well  as  some 
clayey  materials.  The  rock  was  usually  covered  by  a  few  feet 
of  sand,  gravel  and  boulders  intermixed;  but  in  places  where 
the  rock  surface  was  at  some  distance  below  the  tunnel  grade, 
the  material  to  be  met  was  quicksand.  The  nearest  parallel 
in  work  previously  done  was  found  in  some  of  the  tunnels  under 
the  Thames  River,  England,  and  particularly  in  the  Blackwell 
tunnel,  where  open  gravel  was  passed  through. 

The  contract  covering  this  section  of  the  work  was  entered 
into  with  S.  Pearson  &  Son  on  July  7,  1904.  This  contract 
covered  the  permanent  shafts  in  New  York  City  and  in  Long 
Island  City,  the  tunnels  between  these  shafts,  and  their 
extension  eastward  in  Long  Island  City  to  East  Avenue,  involv- 
ing about  23,600  feet  of  single-track  tunnel.  The  contract  had 
many  novel  features  and  seemed  to  be  peculiarly  suitable,  con- 
sidering the  unknown  risks  involved  and  the  unusual  magnitude 
of  the  work. 

A  fixed  amount  was  named  as  the  contractor's  profit.  If 
the  actual  cost  of  the  work  when  completed,  including  the  sum 
named  as  contractor's  profit,  should  be  less  than  a  certain 
estimated  sum  named  in  the  contract,  the  contractor  should 
have  one-half  of  the  saving.  If  on  the  other  hand  the  actual 
cost  of  the  completed  work,  including  the  fixed  sum  for  con- 
Ill 


112      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

tractor's  profit,  should  exceed  the  estimated  cost  named  in  the 
contract,  the  contractor  should  pay  one-half  the  excess  and 
the  railroad  company  the  other  half.  The  contractor's  liability, 
however,  was  hmited  to  the  amount  named  for  a  profit  plus 
$1,000,000.  In  other  words,  his  maximum  money  loss  would 
be  $1,000,000.* 

The  plant  assembled  by  S.  Pearson  &  Son  for  handling  this 
section  is  believed  to  be  the  most  extensive  ever  placed  on  a 
single  piece  of  contract  work.  The  minimum  plant  to  be  pro- 
vided by  the  contractors  for  the  undertaking  was  specified  by 
the  railroad  company  in  part  as  follows:  The  tunnels  were  to 
be  driven  eastward  from  shafts  in  Manhattan  Island  and  west- 
ward from  the  temporary  shaft  to  be  built  near  East  Avenue 
in  Long  Island  City,  making  a  total  of  eight  headings,  in  all 
of  which  work  was  to  be  prosecuted  simultaneously  with  the 
utmost  practicable  diligence.  The  contractor  was  to  provide 
on  each  side  of  the  river  an  adequate  plant  which  was  to  include 
boilers,  air  compressors,  hydraulic  machinery,  dynamos  and 
all  other  necessary  equipment,  with  a  reasonable  duplication 
to  meet  unusual  and  unexpected  emergencies. 

The  air  compressors  were  to  be  of  sufficient  capacity  to 
deliver  regularly  into  each  heading  at  least  300,000  cubic  feet 
of  free  air  per  hour  at  a  pressure  of  50  pounds  per  square  inch 
above  the  normal  air  pressure;  and  for  a  larger  amount  if  found 
necessary  during  the  progress  of  the  work.  The  air  for  the 
compressors  was  to  be  drawn  from  the  exterior  of  the  power 
house  and  the  intake  was  to  be  so  located  as  to  give  pure  air. 
This  air  was  to  be  cooled  and  freed  as  completely  as  possible 
from  oil  and  other  impurities  before  delivering  into  the  heading. 

In  order  to  provide  a  reasonable  margin  for  repairs  and 
contingencies,  a  spare  compressor  and  boiler  plant  was  to  be 
provided  on  each  side  of  the  East  River,  and  to  be  kept  in  good 
condition,  ready  for  immediate  use.  The  capacity  of  these 
spare  plants  was  to  be  25  per  cent  of  that  required  in  the 
preceding  paragraph  for  regular  operation. 

*From  paper  by  Alfred  Noble,  Past  President  Am.  Soc.  C.E.  in  the  Proceed- 
ings of  the  A.S.  of  C.E.  for  September,  1909. 


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THE  EAST   RrVER   TUNNELS  113 

Effective  means  were  to  be  used  to  secure  proper  ventila- 
tion. The  amount  of  carbonic  acid  at  any  working  face  or  in 
any  chamber  must  never  exceed  one  part  in  one  thousand  parts 
of  air.  Suitable  devices  were  to  be  used  to  deaden  as  much 
as  practicable  the  noise  of  the  air  introduced  and  exhausted. 
When  blasting  was  to  be  resorted  to,  special  means  were  to  be 
provided  for  the  rapid  removal  of  the  fumes  produced. 

Bulkheads  were  to  be  built  in  each  tunnel  at  intervals  of 
not  more  than  looo  feet;  and  it  was  specified  that  there  should 
at  no  time  be  an  interval  of  more  than  looo  feet  between 
a  shield  and  the  nearest  bulkhead.  These  bulkheads  were  to 
be  of  concrete  or  brick  set  in  Portland  cement  mortar,  or  of 
other  construction  to  be  approved  by  the  company's  engineer. 
Each  was  to  be  provided  with  two  air  locks  near  the  bottom, 
at  least  6  feet  in  diameter  and  20  feet  in  length,  for  the  passage 
of  men  and  materials;  one  near  the  roof  as  an  emergency  lock 
for  the  passage  of  men  only;  and  a  pipe  12  inches  in  diameter 
and  30  feet  long  with  a  gate  valve  at  each  end,  for  passing 
pipes  and  rails.  The  emergency  lock  was  to  be  of  dimensions 
sufficiently  ample  to  contain  the  entire  force  employed  at  any 
one  time  in  the  heading. 

Stairways  and  galleries  were  always  to  be  maintained  to 
give  sufficient  access  to  the  locks.  All  parts  of  the  bulkheads 
and  air  locks  were  specified  to  be  of  sufficient  strength  to  sus- 
tain safely  a  pressure  of  55  pounds  per  square  inch.  The 
pipes  necessary  for  air  supply,  ventilation,  hydraulic  and  elec- 
tric transmission,  and  other  purposes  were  to  be  built  into  the 
bulkhead  and  provided  with  suitable  connections.  All  of  these 
pipes  were  to  be  standard  lap  welded.  When  a  shield  had  been 
driven  500  feet  or  more  from  the  shaft  it  was  specified  that  at 
least  two  bulkheads  should  always  be  in  use  if  compressed  air 
was  being  used. 

A  safety  screen  extending  from  the  roof  downward  into 
the  tunnel,  of  a  design  to  be  approved  by  the  company's  engineer, 
was  to  be  maintained  within  100  feet  of  each  working  face. 
Others  were  to  be  built  at  intermediate  points  between  the 
working  face  and  the  nearest  bulkhead,  if  necessarv.  to  main- 


114  SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

tain  a  chamber  filled  with  compressed  air  along  the  tunnel 
roof  which  would  give  access  to  the  emergency  lock.  The 
galleries  were  to  extend  from  the  safety  screen  nearest  the  work- 
ing force  to  the  first  bulkhead. 

The  shields  were  to  be  of  ample  strength  and  of  the  best 
materials;  were  to  be  provided  with  hydraulic  rams  of  sufficient 
power  to  move  them  along  the  alignment  laid  down  on  the  plans 
and  profiles;  and  they  were  to  have  adequate  arrangements 
for  the  rapid  execution  of  the  work  and  for  the  safety  of  the  men 
employed. 

These  outline  specifications  were  of  help  to  the  contractors 
in  making  their  bids  and  deciding  what  plant  should  be  installed. 
The  plant  put  in  by  S.  Pearson  &  Son  fulfilled  these  requirements, 
but  it  was  found  that  the  porous  materials  overlying  the  tunnels 
increased  the  demand  for  air  beyond  that  specified,  and  it 
became  necessary  to  increase  the  plant. 

In  the  effort  to  select  the  best  air  compressors  for  continuous 
day-and-night  service  under  the  peculiarly  difficult  conditions 
of  this  work,  the  contractor  made  a  careful  investigation  of 
plants  erected  by  various  manufacturers  wherever  available. 
Indicator  cards  of  the  steam  and  air  cylinders  were  taken  by 
the  contractor's  engineers  where  the  plants  were  within  reasonable 
distance;  and  where  the  plants  were  located  too  far  away, 
indicator  cards  were  submitted  for  inspection. 

After  an  exhaustive  study  of  all  the  machines  proposed  and 
of  their  relative  merits,  it  was  decided  to  adopt  the  type  of 
Ingersoll-Rand  air  compressor  fitted  with  the  latter  company's 
air- thrown  inlet  and  discharge  valves,  on  account  of  the  larger 
valve  areas,  the  free  openings  for  inlet  and  discharge,  and  the  re- 
duced clearance  spaces.  This  compressor  was  chosen  in  preference 
to  other  types  with  poppet  discharge  valves,  as  a  high  piston 
speed  was  necessary  on  account  of  the  limited  area  at  the  dis- 
posal of  the  contractor  for  the  installation  of  his  plant.  The 
choice  of  this  type  was  amply  justified  as,  during  the  four  years' 
operation  of  the  plant,  it  was  never  necessary  to  replace  any 
of  the  forged  steel,  oil  treated  valves. 

There  were  four  cross-compound  steam  duplex  air  low  pres- 


U-ii)fthotBUUdii]g  15U  ft. 
PJan  of  the  Manhattan  Air  Compressor  Plant  for  Pennsylvajiia  R.R.  Kast   Hivcr  Tunnds.   This  was  the  Largest,  Most  Complete  Air  Power  Plant  ever  usee!  for  Contract  Work. 


i 


THE  EAST  RIVER  TUNNELS 


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sure  units,  with  steam  cylinders  i6  and  34  inches  in  diameter, 
air  cyhnders  26 j  inches  in  diameter,  and  a  stroke  of  42  inches. 
They  compressed  to  50  pounds  pressure,  with  an  aggregate 
free  air  capacity  of  14,744  cubic  feet  per  minute.  A  fifth  machine 
was  of  the  same  type,  same  stroke  and  with  steam  cyhnders  of 
the  same  size,  as  the  four  previous  units;  but  it  had  i5j-inch 
duplex  air  cylinders  designed  to  compress  to  140  pounds.  The 
in  take  of  this  latter  compressor  could  be  at  atmosphere,  or 


Interior  of  Manhattan  Air  Compressor  Plant,  P.  R.  R.  East  River  Tunnels. 

at  the  discharge  pressure  of  the  four  low  pressure  units,  the 
latter  increasing  its  delivery  at  high  pressure  about  four  times. 
The  piston  displacement  of  this  machine  was  13 10  cubic  feet 
per  minute  at  normal  speed. 

The  steam  ends  of  these  air  compressors  were  of  cross- 
compound  Corliss  type  with  trip  release  gear  controlled  by  the 
governor  on  each  cylinder.  The  steam  cylinders  and  inter- 
mediate receiver  were  steam  jacketed  and  a  steam  separator 
was  mounted  on  the  throttle  valve.     Steam  was  admitted  at 


116      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

a  boiler  pressure  of  150  pounds  (Stirling  boilers)  and  the  exhaust 
carried  to  Wheeler  condensers  at  about  a  26-inch  vacuum. 
A  test  made  to  determine  the  steam  consumption  gave  14.2 
pounds  of  steam  per  i.h.p.  hour  when  compressing  up  to  30 
pounds  per  square  inch.  An  efficiency  test  of  the  low  pressure 
compressor  units  on  the  Manhattan  side  showed  a  mechanical 
efficiency  of  over  90  per  cent  and  a  volumetric  efficiency  of 
about  96  per  cent. 

In  order  to  cover  the  demand  of  the  specifications  for  a  spare 
plant  of  25  per  cent  capacity,  a  combination  machine  was 
designed  which  could  be  used  either  as  a  high  pressure  machine 
for  rock  drills  or  as  a  low  pressure  machine  for  supplying  tunnel 
air.  It  had  the  same  steam  end  as  the  low  pressure  units,  but 
was  fitted  with  two  low  pressure  cylinders  of  221-inch  diameter 
and  two  high  pressure  cylinders  of  i5j-inch  diameter.  Running 
as  a  low  pressure  machine  with  all  four  air  cylinders  operating, 
it  had  a  capacity  of  5,000  cubic  feet  of  free  air  per  minute.  If 
it  was  desired  to  run  it  as  a  high  pressure  machine,  the  two  low 
pressure  cylinders  could  be  disconnected,  when  the  capacity 
was  1568  cubic  feet  of  free  air  to  90  pounds  pressure  with  atmos- 
pheric intake,  and  6900  cubic  feet  of  free  air  to  140  pounds  pres- 
sure with  an  intake  of  50  pounds  from  the  low  pressure  units. 
Each  air  compressor  was  fitted  with  a  vertical  low  pressure 
aftercooler,  57  inches  in  diameter  and  142  feet  long,  having 
920  square  feet  of  cooling  surface.  These  aftercoolers  were 
fitted  with  tinned  navy-mixture  brass  tubes  and  Tobin  bronze 
tube  plates.  The  air  from  each  compressor  was  discharged 
into  individual  low  pressure  air  receivers,  45  feet  in  diameter 
and  12  feet  high. 

In  addition  to  the  steam  driven  low  pressure  machines 
it  became  necessary  on  the  Long  Island  City  side  to  purchase 
two  low  pressure  Laidlaw-Dunn-Gordon  electrically  driven 
compressors.  Each  of  these  had  two  air  cylinders,  30  inches 
in  diameter  by  42-inch  stroke,  with  rotative  inlet  valves.  They 
were  designed  for  a  speed  of  75  r.p.m.  with  a  rope  driven 
fly-wheel  20  feet  in  diameter  weighing  20  tons  and  carrying 
fourteen  2-inch  ropes.     Horizontal  aftercoolers  of  1000  square 


TUE  EAST  RIVEK   TUNXELS 

? 


117 


118      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

feet  of  cooling  surface  each  were  attached,  and  the  air  was 
discharged  into  receivers  4^  by  12  feet.  These  units  were  driven 
by  Westinghouse  600  h.p.,  440  volt,  three-phase,  25-cycle 
motors  running  at  300  r.p.m.  with  a  rope  sheave  5  feet  2  inches 
in  diameter.  The  motors  took  their  current  from  three  trans- 
formers of  375  kw.  each,  oil  insulated  and  water  cooled,  receiv- 
ing current  at  11.000  volts  and  transforming  it  down  to  440 
volts. 

The  great  disadvantage  of  these  electrically  driven  air 
compressors  was  that  there  was  no  way  to  regulate  the  volume 
of  air  discharged,  as  the  speed  of  the  motor  could  not  be  changed. 
The  usual  method  of  operating  them  was  to  open  out  on  two  or 
more  tunnels  requiring  more  than  their  combined  capacity,  and 
to  adjust  the  volume  of  air  by  means  of  one  of  the  steam 
driven  units. 

As  stand-by  high  pressure  machines  for  the  Manhattan 
side  when  the  combination  machines  were  on  low  pressure  duty, 
two  Ingersoll-Rand  duplex,  simple  steam,  2-stage  air  com- 
pressors were  installed  with  steam  cylinders  16  inches  in  diameter 
and  air  cylinders  25I  and  i6j  inches  in  diameter.  The  stroke 
of  these  units  was  16  inches  and  each  had  a  capacity  of  1205 
cubic  feet  of  free  air  per  minute. 

On  the  Long  Island  City  side  where  little  rock  was  encountered 
an  Ingersoll-Rand  ''  Imperial  "  compressor  was  installed  as  a 
stand-by  while  the  combination  machine  was  used  on  low 
pressure  duty.  This  was  a  duplex,  simple  steam,  2-stage  air 
compressor,  with  16-inch  steam  cylinders,  15-  and  25-inch  air 
cylinders  and  20-inch  stroke.  Its  capacity  was  1070  cubic 
feet  of  free  air  per  minute  at  100  pounds  pressure. 

For  starting  up  the  headings  at  the  East  Avenue  side  at 
Long  Island  City,  two  Ingersoll-Rand  straight  line  compressors 
were  used,  with  steam  cylinder  18  inches  in  diameter,  air 
cylinder  i8i  inches  and  a  24-inch  stroke.  At  90  r.p.m.  each 
had  a  capacity  of  656  cubic  feet  of  free  air  per  minute  compressed 
to  90  pounds. 

As  there  were  ultimately  two  electrically  driven  air  com- 
pressors on  the  Long  Island  side,  and  six  low  pressure  units 


THE  EAST  RIVER  TUNNELS  119 

and  one  combination  unit  on  each  side  of  the  river;  and  as 
these  machines  were  guaranteed  to  run  at  125  r.p.m.  con- 
tinuously for  twenty-four  hours,  the  maximum  free  air  capacity 
of  all  the  compressors,  including  the  high  pressure  units, 
amounted  to  102,922  cubic  feet  per  minute. 

Steam  at  150  pounds  pressure  was  generated  in  twelve  Stirling 
water  tube  boilers  (six  on  each  side  of  the  river),  each  having 
a  capacity  of  500  h.p.  with  10  square  feet  of  heating  surface 
per  h.p.  and  0.25  square  foot  of  grate  surface  per  h.p.  The 
grates  were  8  feet  deep,  and  were  of  the  McClave  shaking  t}pe. 
Each  boiler  occupied  a  space  19  feet  9^  inches  by  18  feet  3  inches, 
and  was  about  21  feet  high.  Each  had  an  independent  steel 
stack  54  inches  in  diameter  and  100  feet  above  grate  level. 
The  boilers  were  guaranteed  to  evaporate  8.7  pounds  of  water 
per  pound  of  dry  coal  having  a  heat  value  of  not  less  than  12,000 
B.t.u.  and  not  more  than  15  per  cent  of  ash,  from  and  at  212 
degrees  Fahrenheit  with  a  pressure  in  the  ash  pit  of  not  less  than 
2  inches  and  a  draft  at  the  damper  box  of  0.75  inch.  This 
result  was  to  be  obtained  with  either  No.  2  or  i  buckwheat 
anthracite;  and  in  testing  it  was  found  that  the  boilers  exceeded 
this  eflSciency. 

In  computing  the  boiler  capacity  necessary,  it  was  originally 
estimated,  before  finally  deciding  on  the  whole  plant,  that  the 
i.h.p.  requirements  on  each  side  of  the  river  would  be  as 
follows:  Electrical  plant,  580;  air  compressors,  3325;  hydrauHc 
plant,  202;  total,  4107  i.h.p.  using  68,300  pounds  of  steam 
per  hour.  On  the  basis  of  eight  pounds  of  water  evaporated  per 
pound  of  coal,  this  would  represent  8500  pounds  of  coal  per 
hour.  Assuming  four  pounds  of  coal  per  boiler  h.p.,  the 
capacity  would  be  2125  plus  531  (for  the  25  per  cent  spare 
plant)  or  2656  boiler  h.p.  This  was  taken  to  represent  five 
boilers  at  500  h.p.  capacity.  Ultimately  it  became  necessary 
to  increase  the  compressor  plant  and  a  sixth  boiler  was  added 
on  each  side  of  the  river. 

The  boilers  were  arranged  for  forced  draft.  Two  6^-foot 
fans  driven  by  7-inch  by  8-inch  vertical  engines  were  provided 
for   each   plant    of    five    boilers.      At    East   Avenue   in  Long 


120 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


Island  City  there  were  also  four  loo  h.p.  locomotive  boilers. 
These  supplied  steam  to  the  two  straight  line  compressors 
and  also  were  used  for  driving  fan  engines  for  ventilation,  the 
shaft  pumps  and  steam  derricks. 

With  five  boilers  in  operation  the  highest  coal  consumption 
on  the  Manhattan  side  for  any  one  month  was  at  the  rate  of 
800  tons  per  week.     This  is  equivalent  to  1 7  pounds  per  square 


Cameron  Pumping  Plant  in  Pennsylvania  and  Long  Island  R.  R.  Tunnel. 
The  pump  in  the  rear,  nearest  the  air  lock,  is  equipped  with  motor  and 
electrically  driven,  while  the  pump  in  front  is  operated  by  compressed  air. 

foot  of  grate  surface  per  hour  for  five  boilers.  According  to 
the  records  kept,  the  average  consumption  was  2.8  pounds  of 
coal  per  i.h.p.  per  hour  for  all  machinery. 

The  coal  used  on  the  Long  Island  City  side  was  No.  2 
buckwheat.  On  the  ^Manhattan  side  where  a  greater 
demand  was  made  on  the  plant,  No.  i  buckwheat  was 
used.  The  calorific  value  of  the  coal  generally  was  from 
11,500  to  12,900  B.t.u.,  with  ash  varying  from  13  to  20  per 
cent.     As  a  result  of   a   combination  of  poor  coal  and  ineffi- 


THE  EAST   RIVER   TIXXELS 


121 


cient  firemen,   the  actual  ash  from  the  boiler  varied  from  20 
to  30  per  cent.* 

For  ordinary  service  work,  the  most  suitable  pump  for 
;he  rough  work  and  large  volumes  of  water  proved  to  be  the 
Cameron  Xo.  12,  with  18-inch  steam  and  12-inch  water  cylinders, 
and  20-inch  stroke.  At  the  East  Avenue  site  of  the  works,  a 
great  number  of  pumps  were  necessary  in  the  headings  and  break- 


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Photograph  taken  in  Pennsylvania  and  Long  Island  R.  R.  Tunnel.  Cameron 
Station  Pump  handling  the  drainage  water,  which  seeps  through  the  rock 
and  earth  that  separate  the  tunnel  from  the  river  bottom. 

ups;  and  outside  of  the  air-tight  bulkheads  at  the  lower  end 
of  this  section,  the  No.  9  Cameron  pump  was  generally  adopted, 
although  smaller  sizes  were  used  at  various  points.  These 
pumps  took  up  so  little  room  that  they  stood  at  the  side  of  the 
headings  without  interfering  with  the  passage  of  cars. 

*  From  a  paper  by  Henr\-  Japp,  ^I.A.S.C.E.,  on  the  "  Contractor's  Plant  for 
the  East  River  Tunnels  "  in  the  Proceedings  of  the  Am,  Soc.  C.E.  for  Novem- 
ber, 1509. 


122      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

Besides  other  qualities,  the  points  of  excellence  peculiar 
to  the  Cameron  design  are  simpUcity,  durability  and  the  entire 
absence  of  outside  valve  gear  or  other  moving  parts.  This 
pump  has  fewer  working  parts  than  any  other  pump ;  the  steam 
mechanism  consists  of  four  stout  pieces  only,  none  of  them 
delicate,  intricate  or  exposed  to  injury.  While  under  full  pres- 
sure of  steam  the  suction  pipe  may  be  lifted  out  of  water  and  the 
pump  allowed  to  run  away  or  race  as  fast  as  steam  will  drive 
it,  without  danger  of  the  piston  striking  the  heads  or  any  injury 
to  the  pump.  Under  most  conditions  as  found  on  construction 
work,  any  pump  is  liable  to  have  its  supply  of  water  cut  oS 
unexpectedly.  With  pumps  of  other  design  the  sudden  removal 
of  the  working  load  quite  frequently  results  in  the  breaking  of 
cyhnder  heads  or  other  derangement  that  puts  the  machine  out 
of  service.  The  absence  of  outside  gear  of  any  kind  permits 
the  operation  of  this  pump  under  adverse  conditions  or  rough 
usage.  Instances  have  occurred  where  this  pump  has  started 
off  and  cleared  a  shaft  of  water  when  the  pump  itself  had  been 
buried  for  weeks  under  a  mass  of  fallen  rock  and  debris. 


CHAPTER  XV 

THE  EAST  RIVER  TUNNELS   OF   THE   PENNSYLVANIA  RAILROAD 

(Coiithiucd) 

There  were  two  types  of  shields  used  in  carrying  on  this 
section  of  the  work :  The  heavy  type  used  in  the  tunnels  under 
the  river,  and  a  lighter  type  used  in  driving  the  land  tunnels 
from  the  East  Avenue  shaft,  Long  Island  City,  under  the  Long 
Island  Station.  The  type  used  under  the  river  was  designed 
by  Mr.  E.  W.  Moir,  Vice  President  of  S.  Pearson  &  Son,  and  was 
similar  to  that  used  in  the  Blackwell  Tunnel,  England,  also 
designed  by  Mr.  Moir.  The  principal  feature  distinguishing 
these  shields  from  those  used  in  the  land  section  and  from 
others  used  in  subaqueous  work  around  New  York  was  their 
massive  construction.  The  cutting  edges  were  made  very 
heavy,  yet  they  proved  none  too  heavy  for  the  work  before 
them.  The  cutting  edge  of  one  of  them  was  turned  up  by 
being  pushed  on  an  almost  imperceptible  incline  of  rock  and 
had  to  be  repaired  under  air  pressure.  The  total  weight  of 
each  of  these  shields,  without  jackets  or  erectors,  was  185  net 
tons. 

Eight  subaqueous  shields  were  used,  23  feet  6\  inches  in 
outside  diameter,  with  horizontal  floors  projecting  9  inches 
in  advance  of  the  cutting  edge  between  the  vertical  diaphragms 
and  running  back  to  the  line  of  the  cutting  edge  on  each  side. 
They  were  divided  into  nine  pockets  by  two  vertical  diaphragms 
and  two  horizontal  floors.  The  latter  were  made  up  of  two  plates 
f  of  an  inch  thick,  and  were  non-continuous  for  a  width  of  6 
feet  10  inches,  butting  against  the  vertical  diaphragms  which 
were  continuous  for  a  width  of  6  feet  10  inches. 

The  outer  shield  was  made  up  of  three  skin  plates  of  |-inch 

123 


124      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

steel,  the  outer  and  middle  plates  being  17  feet  6  inches  long. 
The  inner  plate  was  17  feet  3  inches  long. 

The  skin  plates  were  divided  up  around  the  circumference 
in  such  a  way  that  the  shields  could  be  built  for  transportation 
in  eight  sections,  including  the  hydraulic  jack  boxes.  The 
middle  and  inner  skin  plates  lapped  the  outer  plates  by  12  inches 
and  24  inches  respectively. 

In  addition  to  the  two  vertical  diaphragms  there  were  two 
transverse  bulkheads,  2  feet  6  inches  apart,  completely  closing 
the  shields  except  for  openings  made  for  doors  and  muck  chutes. 
For  each  floor  there  was  a  pair  of  doors,  one  in  each  transverse 
bulkhead;  and  nine  muck  chutes  pierced  both  bulkheads, 
with  hinged  doors  on  either  end.  A  safety  screen  about  4  feet 
wide  and  7  feet  deep  shrouded  and  surrounded  the  doors  open- 
ing from  the  upper  chamber.  A  drop  safety  curtain,  i  foot  6 
inches  deep  and  f  of  an  inch  thick,  was  fixed  along  the  roof 
of  each  chamber.  The  cutting  edge  was  of  cast  steel,  divided 
into  segments  machined  on  the  radial  joints  and  bolted  together 
with  turned  and  fitted  bolts. 

The  benefit  of  having  the  two  transverse  bulkheads  was 
to  give  the  shield  an  added  stiffness  which  it  required.  The 
smallness  of  the  doors  and  the  muck  chutes  through  these 
bulkheads  handicapped  for  a  while  the  mucking-out  operations, 
especially  in  rock.  After  it  was  found  that  there  was  no  likeli- 
hood of  this  feature  being  required,  the  transverse  bulkhead  in  all 
three  bottom  pockets  was  cut  out  and  the  middle  bottom  pocket 
utilized  for  running  the  tunnel  cars  through  the  shield  into  the 
heading  beyond  on  the  tunnel  track. 

To  facilitate  the  passage  of  drill  columns  and  timber  to  the 
upper  pockets,  part  of  the  center  pocket  transverse  bulkhead 
was  also  cut  away.  The  18-inch  curtain  suspended  from  the 
under  side  of  each  floor  18  inches  in  front  of  the  bulkhead 
provided  an  air  space  for  the  men  into  which  they  could  duck 
their  heads  if  the  shield  was  flooded.  As  the  conditions  obtain- 
ing under  the  East  River  had  never  been  explored  by  a  previous 
tunnel  at  the  time  this  shield  was  started,  many  and  varied 
contingencies  were  provided  for  in  the  accessories  of  the  shield 


I 


THE  EAST  RIVER  TUNNELS  125 

which  would  not  be  necessary  in  future  work  under  this  river. 
The  most  satisfactory  arrangement,  in  any  type  or  mixture 
of  types  of  materials  found  under  the  river  was  the  bare  shield, 
with  the  fixed  hood  projecting  3  feet  in  advance  of  the  cutting 
edge  for  about  two-fifths  of  the  circumference,  and  no  extension 
floors  except  those  formed  by  sliding  timber  extensions  which 
could  readily  be  replaced  without  damage. 

After  extensive  tests  on  various  makes  of  drills  the  Ingersoll- 
Rand  "  E-52  "  3|-inch  rock  drill  was  adopted  for  this  work.  It 
was  found  to  use  less  air  than  any  other  make  and  to  stand  up 
to  the  work  equally  well,  if  not  better.  These  machines  had 
exceptionally  hard  service  on  account  of  the  seamy  nature 
of  the  rock.  They  were  generally  mounted  on  standard  drill 
columns  set  up  in  the  pockets  of  the  shields,  except  where 
advance  headings  were  being  driven. 

In  addition  to  these  standard  rock  drills  a  number  of  Ingersoll- 
Rand  hand  hammer  or  plug  drills  were  used  for  trimming  and 
breaking  up  lumps  of  rock. 

In  the  tunnels  working  under  compressed  air,  no  pumps 
were  necessary  in  the  air  chamber,  as  the  air  pressure  blew  the 
water  out  from  the  pipes  to  the  sump.  It  was  possible  under 
special  circumstances,  by  allowing  air  to  leak  into  the  pipe 
from  the  chamber,  for  the  water  to  be  delivered  right  up  into 
the  river  without  the  use  of  pumps.  But  generally  it  was  found 
more  reliable  to  blow  the  water  from  the  tunnel  to  the  shafts 
and  to  pump  it  from  there. 

At  the  foot  of  each  shaft,  as  a  stand-by  in  the  event  of 
flooding,  one  special  6-inch  vertical  pump  was  installed  capable 
of  delivering  60,000  gallons  per  hour.  Two  Ajax  drill  sharpen- 
ers were  used,  one  on  the  Manhattan  side  and  the  other  at 
Long  Island  City.* 

There  were  two  permanent  shafts  on  each  side  of  the  East 
River  and  four  single-track  cast-iron  tube  tunnels,  each  about 
6000  feet  long  and  consisting  of  about  3900  feet  between  shafts 
under  the  river  and  about  2000  feet  in  Long  Island  City,  mostly 

*  From  "  Contractor's  Plant  for  the  East  River  Tunnels,"  by  Henry  Japp, 
M.A.S.C.E.,  in  the  Proceedings  of  the  Am.  Soc.  C.E.,  November,  1909. 


126      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

under  the  station  and  passenger  yards  of  the  Long  Island  Rail- 
road. An  average  of  1760  feet  of  tunnel  was  driven  from  Man- 
hattan, and  2142  feet  from  Long  Island  westward.  Ground 
was  broken  on  May  17,  1904.  Five  years  later  to  a  day,  the 
work  was  finished  and  received  final  inspection  for  acceptance 
by  the  railroad  company. 

The  work  was  carried  on  from  three  sites,  as  follows :  From 
permanent  shafts  located  near  the  river  in  Manhattan,  four 
shields  were  driven  eastward  to  about  the  middle  of  the  river; 
from  two  similar  shafts  at  the  river  front  in  Long  Island  City, 
four  shields  were  driven  westward  to  meet  those  from  Man- 
hattan; from  a  temporary  shaft  near  East  Avenue,  Long  Island 
City,  the  land  section  of  about  2000  feet  was  driven  westward 
to  the  river  shafts. 

In  the  description  which  follows  the  cost  of  work  will  be 
given  under  two  terms.  "  Unit  labor  "  will  be  the  cost  of  labor 
directly  chargeable  to  the  operation  considered.  "  Top  charges  " 
will  include  the  cost  of  the  plant  and  its  operation,  the  cost  of 
the  contractor's  staff  and  roving  labor,  such  as  electricians, 
pipe  men,  yard  men  and  all  miscellaneous  labor.  But  it  does 
not  include  materials  entering  into  the  permanent  work,  or  con- 
tractor's profit. 

Working  east  from  the  Manhattan  shaft  the  formations 
were  in  succession  as  follows:  123  feet  of  all  rock  section;  87 
feet  of  all  earth  and  rock;  723  feet  of  all  earth  section;  515 
feet  of  all  earth  and  rock;  291  feet  of  all  rock  section;  and  56 
feet  of  part  rock  and  part  earth. 

The  rock  was  Hudson  schist  and  Fordham  gneiss.  The 
latter  was  slightly  the  harder  and  both  were  badly  seamed  and 
fissured.  When  the  rock  surface  was  encountered  it  was  cov- 
ered with  a  deposit  of  boulders,  gravel  and  sand  varying  in  thick- 
ness from  4  to  10  feet.  The  rock  near  the  surface  on  the  Man- 
hattan side  was  broken  up  and  full  of  disintegrated  seams; 
and  it  was  irregular  in  stratification,  dipping  toward  the  west 
at  about  60  degrees.  The  rock  surface  was  very  irregular  and 
was  covered  with  boulders  and  detached  masses  of  rock  bedded 
in  coarse  sand  and  gravel.     From  the  latter  material  air  escaped 


LOCKS    N  NO  1  BULKHEmD    TUNNEL    1 


I 


THE  EAST  RIVER  TUNNELS  127 

freely.  When  the  shields  had  entirely  cleared  the  rock  the 
material  in  the  face  had  changed  to  a  tine  sand,  stratified  every 
few  inches  by  very  thin  layers  of  chocolate-colored  clayey 
material.  This  is  elsewhere  referred  to  as  quicksand.  As 
the  shield  advanced  eastward,  the  number  and  thickness  of  the 
layers  of  clay  increased  until  the  clay  formed  at  least  20  per  cent 
of  the  entire  mass,  and  many  of  these  layers  were  2  inches  in 
thickness.  About  440  feet  beyond  the  Manhattan  ledge,  the 
material  at  the  bottom  changed  suddenly  to  about  98  per  cent 
clay.  The  sand  layers  were  not  more  than  ^  of  an  inch  thick, 
averaging  2  inches  apart. 

The  surface  of  the  sand  and  gravel  was  irregular  but  rising 
gradually.  After  rock  was  encountered  the  formations  of 
rock  and  clay  were  roughly  parallel  to  the  rock  surface;  as  the 
surface  of  the  rock  rose  they  disappeared  in  order  and  were 
again  encountered  when  the  shields  broke  out  of  rock  on  the 
east  side  of  Blackwell's  Island  reef.  East  of  the  reef  a  large 
quantity  of  coarse  open  sand  was  present  in  the  gravel  forma- 
tion before  the  clay  appeared  below  the  top  of  the  cutting  edge. 
Wherever  the  clay  extended  above  the  top  of  the  shield  it  reduced 
the  escape  of  air  very  materially. 

While  sinking  the  lower  portions  of  the  shafts  the  tunnels 
were  excavated  eastward  in  the  solid  rock  for  a  distance  of  about 
60  feet,  where  the  rock  at  the  top  was  found  to  be  somewhat 
disintegrated.  This  was  as  far  as  was  considered  prudent  to 
go  with  the  full-sized  section  without  air  pressure.  At  about 
the  same  time  top  headings  were  excavated  westward  from  the 
shafts  for  a  distance  of  100  feet,  and  these  headings  enlarged 
to  full  size  for  a  distance  of  about'  50  feet. 

The  shields  were  erected  in  the  shafts,  and  were  shoved 
forward  to  the  face  of  the  excavation.  Concrete  bulkheads 
with  the  necessary  air-locks  were  then  built  across  the  tunnels 
behind  the  shields.  The  shields  were  shoved  eastward  for 
about  60  feet  and  the  permanent  tunnel  lining  erected  as  the 
shield  advanced.  Before  leaving  the  rock,  air  pressure  was 
necessary  in  the  tunnels  and  this  necessitated  the  building  of 
bulkheads  with  air-locks  inside  the  cast   iron  linings  just  east 


128      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

of  the  portals.  Before  erecting  the  bulkheads  it  was  necessary 
to  close  the  annular  space  between  the  iron  tunnel  lining  and  the 
rock. 

The  space  at  the  portal  was  filled  with  the  concrete  wall. 
After  about  twenty  permanent  rings  had  been  erected  in  each 
tunnel,  two  rings  were  pulled  apart  at  the  tail  of  the  shield  and 
a  second  masonry  wall  or  dam  was  built.  The  space  between 
the  two  dams  was  then  filled  with  grout.  To  avoid  the  pos- 
sibility of  pushing  the  iron  backward,  after  the  air  pressure 
was  put  on,  rings  formed  of  segmental  plates  f  of  an  inch  thick 
and  13 1  inches  wide  were  inserted  in  18  of  the  circumferential 
joints  in  each  tunnel  between  the  rings  as  they  were  erected. 
When  these  rings  were  in  position  they  projected  about  15 
inches  beyond  the  alignment  and  when  the  tunnel  was  grouted 
they  were  bedded  in  the  cement.  The  bulkheads  were  com- 
pleted, and  the  tunnels  put  under  air  pressure.  In  the  deepest 
part  of  the  river  near  the  pier  head  line  on  the  Manhattan  side, 
there  was  only  8  feet  of  natural  cover  over  the  tops  of  the  tunnels ; 
and  this  was  a  fine  sand  which  was  certain  to  allow  air  to  escape 
freely.  A  blanket  of  clay,  averaging  10  or  12  feet  in  thickness 
was  dumped  over  the  line  of  work.  It  was  found  to  be  of 
material  advantage,  but  its  depth  was  insufiicient  to  entirely 
stop  the  loss  of  air. 

The  shields  in  each  pair  of  tunnels  were  advanced  through 
the  solid  rock  section  about  abreast  with  each  other,  until  the 
test  holes  from  the  faces  indicated  soft  ground  within  a  few 
feet.  As  the  distance  between  the  sides  of  the  tunnels  was 
only  14  feet,  the  two  center  tunnels  were  given  a  lead  of  100  feet 
from  this  point  as  a  precaution  against  a  blow  extending  from 
one  tunnel  to  another. 

When  the  shields  in  two  of  the  tunnels  in  soft  ground  from 
Manhattan  reached  the  bulkhead  Hne,  work  was  partly  suspended 
and  shutters  put  in  place  in  the  top  and  center  compartments 
of  the  face  of  the  shield.  These  shutters  were  moved  in  and 
out  by  screws  on  the  ends  of  the  shutters.  Similar  shutters  had 
been  used  with  marked  success  in  loose  open  material  in  the 
Blackwell  Tunnel.     In  operating,  the  shutters  were  forced  by 


AF  BACK   ELEVATION  OF  SHUTTERS,  SHOWING  SLIDES 

FiG.7 


Method  of  Shield  Driving,  Pennsylvania  U.R.  East  River  Tunnels. 


thp:  p:ast  hiver  tunnels 


129 


the  screws  against  the  face  and  material  removed  through  the 
doors  during  the  process.  As  pressure  was  applied  to  the  shield 
jacks  the  shutters  were  allowed  to  slide  back  into  the  shield 
chambers,  the  screws  being  slacked  back.  In  preparing  for  a 
new  shove  the  slides  in  the  shutters  were  opened  and  the  material 
in  front  raked  into  the  shield. 

No  shutters  were  placed  in  the  bottom  compartments  and 
as  the  air  pressure  was  not  generally  high  enough  to  keep  the 


^^HHP^HP^^vHHWHMRi^^HPil 

^^HH 

^^H 

W:  *  'j^Fjiff^^^StSBm^^B^B^BS^^Si^^^^S^SlSKSii 

k^J^^9 

^^V^^l 

K^B^iflB^l^^f^^S^9^3S'V^^^^^Bifeh9Pl^^^BS 

lik^^ftL 

^V  '*~H 

■VlVv&^^P'Is^^^S    "^^V^M^^K^H 

^^hJ 

1 

mS. 

■i      tHSSfk 

jlH 

Rear  of  Shield  showing  Complete  Fittings. 

face  dry  at  the  bottom,  these  lower  compartments  were  pretty 
well  filled  with  a  soft,  wet  quicksand.  Much  of  the  excavation 
in  the  bottom  compartment  was  done  by  a  blow-pipe.  During 
the  shove  the  material  from  the  bottom  compartment  often 
ran  back  through  the  open  door  in  the  transverse  bulkhead. 
In  the  Blackwell  Tunnel,  the  material  was  loose  enough 
to  keep  in  contact  with  the  shutters  at  all  times.  This  was  not 
the  condition  in  the  East  River  tunnels;  the  sand  at  the  top 
was  drv  and  would  often  stand  with  a  vertical  face  for  some  hours. 


130      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

In  advancing  the  shutters  it  was  difficult  to  bring  them  in  close 
contact  with  the  face  at  the  end  of  the  operation.  The  soft 
material  at  the  bottom  was  constantly  running  into  the  lower 
compartment  and  undermining  the  stiff  material  at  the  top. 
Under  these  circumstances,  the  air  escaped  freely  through  the 
unprotected  sand  face.  The  points  of  the  shutters  were  plastered 
with  clay,  but  this  did  not  keep  the  air  from  passing  out  through 
the  lower  compartments.     This  condition  facilitated  the  for- 


Shield  Fitted  with  Fixed  Hoods  and  Fixed  Extensions  to  the  Floors. 

mation  of  blowouts  which  were  of  constant  occurrence  where 
the  shutters  were  used  in  sand.  In  one  of  the  tunnels,  the 
shutters  were  placed  in  the  shield  but  never  used  against  the 
face.  Excavation  was  carried  on  by  poling  the  top  and  breasting 
the  face;  and  this  change  resulted  in  much  better  progress  and 
fewer  blowouts. 

Shutters  were  not  placed  on  the  Long  Island  shields.     Before 
the  shield  entered  soft  ground  a  fixed  hood  was  attached  to 


CCNSTRUC     ON  OF  BULKHEAC 


Method  of  Shifkl  Driving,  Penn^lvania  R.H.  li-ajit  River  TunneU. 


THE  EAST  RIVER  TUNNELS 


131 


each.  The  face  was  mined  out  to  the  front  of  the  hood  and 
breasted  down  to  a  little  below  the  floor  of  the  top  pockets  of 
the  shield.  In  the  middle  pockets  the  earth  took  a  natural 
slope  backward  to  the  floor.  In  the  bottom  pockets  it  was  held, 
at  the  back,  by  stop  logs.  The  air  pressure  was  always  about 
equal  to  the  hydrostatic  head  at  the  middle  of  the  shield.  In 
consequence,  the  face  in  the  upper  and  middle  pockets  was 
dry,  but  in  the  lower  pocket  it  was  wet  and  flowed  under  the 


Shield    Fitted  with  Sectional   Slidinff  Hoods  and   Sliding  Exten-sion.s  to   the 

Floors. 

pressure  of  shoving  the  shield.  By  this  method,  4195  lineal 
feet  of  tunnel  were  excavated  by  the  four  Long  Island  shields  in 
120  days  between  November  i,  1907  and  March  7,  1908.  This 
was  an  average  of  8.74  feet  per  day  per  shield. 

Preparatory  to  making  the  final  shove  with  the  shields,, 
special  polings  were  placed  with  unusual  care.  The  Man- 
hattan shields  were  stopped  and  the  excavation  ahead  made 
bell  shape  to  receive  the  Long  Island  shields.  The  shields 
being  shoved  into  final  position,  the  rear  end  of  the  polings 
rested   above   the  hood.     When   this  was  done,   bulkheads  of 


132      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

concrete  and  clay  bags  were  built  to  avoid  blows  when 
the  shields  came  near  each  other.  An  8-inch  pipe  was 
then  driven  forward  to  the  bulkhead  for  from  30  to  100  feet, 
in  order  to  check  the  alignment  and  grade  between  the  two 
workings  before  the  shields  were  actually  shoved  together. 
To  bring  the  cutting  edges  together,  it  was  necessary  to  cut 
away  the  projecting  floors  of  the  working  compartments. 

Operations  were  carried  on  continuously  for  thirteen  days 
out  of  fourteen,  repairs  being  done  on  alternate  Sundays  when 
the  work  was  closed  down.  When  it  was  required  to  have  an 
air  pressure  greater  than  32  pounds,  four  gangs  were  worked, 
each  gang  working  two  3-hour  shifts  with  3-hour  intermission 
between  shifts.  When  the  air  pressure  was  less  than  32 
pounds  three  gangs  were  employed  in  three  8-hour  shifts; 
h  hour  in  low  pressure  was  allowed  for  lunch.  In  soft 
ground  during  the  greater  portion  of  the  work,  the  pressure 
maintained  was  about  equal  to  the  hydrostatic  head  at  the 
axis  of  the  tunnel.  This  was  from  30  to  34  pounds  per  square 
inch  above  atmosphere.  Pressures  as  high  as  37  pounds  were 
maintained  for  extended  periods.  In  firm  material  28  pounds 
was  sufficient.  While  removing  broken  tunnel  plates  42  pounds 
was  carried  for  a  short  time;  but  pressures  of  from  37^  to  40 
pounds  were  maintained  for  more  than  a  month. 


CHAPTER  XVI 

THE  EAST  RIVER  TUNNELS  OF  THE  PENNSYLVANIA    RAILROAD 

(Continued.) 

The  river  shafts  on  the  Manhattan  and  Long  Island  sides 
were  designed  to  serv'e  as  working  shafts  and  permanent  open  ■ 
ings  to  the  tunnels.  As  they  were  practically  identical  on  both 
sides  of  the  river,  a  description  of  the  construction  used  in  Long 
Island  City  will  serve  for  both.  There  were  two  shafts  on  each 
side  of  the  river,  each  shaft  serving  two  tunnels.  Each  con- 
sisted of  a  steel  caisson,  40  by  74  feet  in  dimensions  with  walls 
5  feet  in  thickness,  filled  with  concrete.  Each  shaft  was  divided 
into  two  compartments,  29  by  30  feet,  separated  by  a  wall  6 
feet  thick.  Openings  for  the  tunnels  25  feet  in  diameter  were 
provided  in  the  sides  of  the  caisson,  and  these  openings  were 
closed  during  sinking  by  steel  bulkheads. 

The  shafts  were  sunk  as  pneumatic  caissons  to  a  depth  of 
78  feet  below  mean  high  water  mark.  Most  large  caissons 
go  to  rock  or  a  little  below.  The  unusual  feature  of  these  caissons 
was  that  they  were  sunk  54  feet  through  rock.  The  roof  of 
the  working  chamber  was  7  feet  above  the  cutting  edge.  Each 
chamber  had  two  shafts,  3  by  5  feet  in  cross-section,  with  a 
diaphragm  dividing  it  into  two  passages,  one  for  men  and  one 
for  the  muck  buckets.  On  top  of  these  shafts  were  Moran 
locks.  A  5 -ton  crane  mounted  on  top  of  the  caisson  served  both 
shafts  and  the  muck  cars  on  the  ground  level  beside  the  caisson. 
Circular  steel  muck  buckets  2  h  feet  in  diameter  and  3  feet  high 
dumped  the  muck  into  the  cars  and  returned  to  the  bottom  of 
the  working  chamber  without  unhooking.  Work  was  carried 
on  in  three  8-hour  shifts. 

On  the  Long  Island  side  earth  was  excavated  at  the  rate 
of  67  cubic  yards  per  caisson  per  day.     Rock  excavation  amount- 

133 


134      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

ing  to  about  6200  cubic  yards  in  each  caisson  was  done  at  the 
rate  of  44.5  cubic  yards  per  day.  The  average  rate  of  sinking 
through  earth  was  0.7  foot  per  day;  through  rock,  0.48  per  day 
in  the  south  caisson  and  0.39  in  the  north  caisson.  In  sinking 
the  caissons  100-ton  hydrauUc  jacks  and  wood  blocking  were 
used.  When  lowering,  the  air  pressure  was  reduced  by  about  10 
pounds,  which  increased  the  net  weight  to  more  than  4,000,000 
pounds.  The  caissons  usually  carried  a  net  weight  of  about 
870  tons.  The  concrete  in  them  was  generally  kept  about  at 
the  ground  level.  Water  ballast  5  to  20  feet  in  depth  was  kept 
near  the  roof  of  the  working  chamber.  The  air  pressure  in 
the  chamber  was  generally  less  than  the  hydrostatic  head. 
For  example,  the  average  pressure  in  the  caissons  was  16 1 
pounds  of  air,  while  the  average  head  was  62^  feet  or  27 
pounds  per  square  inch.  The  bottom  of  the  shaft  was  an 
inverted  concrete  arch  4  feet  thick,  waterproofed  with  six-ply 
felt  and  pitch. 

The  cost  of  excavation  in  the  caisson  was  $15.02  per  cubic 
yard,  of  which  $4.48  was  labor  and  $10.54  top  charges.  The 
cost  of  labor  in  compressed  air  chargeable  to  concreting  was 
$3.40  per  cubic  yard.  When  the  roof  of  each  working  chamber 
had  been  removed  the  shield  was  erected  in  a  timber  cradle  in 
the  bottom  of  the  shaft,  in  a  position  to  be  shoved  out  of  the 
opening  in  the  side  of  the  caisson.  Temporary  stays  of  iron 
Hning  were  erected  across  the  shaft  to  furnish  an  abutment  for 
the  jacks. 

The  roof  of  the  working  chamber  was  re-erected  about 
35  feet  above  its  original  position,  bringing  it  about  8  feet  above 
the  tunnel  openings.  Instead  of  the  two  small  shafts  in  use 
during  the  sinking  of  the  caisson,  a  large  steel  T-shaped  head- 
lock  was  built.  This  was  8  feet  in  diameter  and  contained  a  lad- 
der and  elevator-cage  for  men  and  for  standard  i-yard  tunnel 
cars.    In  the  tee  forming  the  top  were  two  standard  tunnel  locks. 

On  the  Manhattan  side  the  south  shaft  was  sunk  in  earth 
at  the  rate  of  about  0.5  foot  per  day  and  the  north  shaft  at  about 
0.53  foot  per  day.  Two  lo-hour  shifts  were  used.  The  average 
rate  of  excavation  in  soft  material  was  84  cubic  yards  per  day; 


THE    EAST    RIVER   TUNNELS  135 

in  rock  below  the  caisson,  125  cubic  yards  per  day.  Earth 
excavation  cost  S3. 96  per  cubic  yard,  of  which  S1.45  was  for 
labor  and  $2.51  top  charges.  Rock  excavation  cost  $8.93  per 
cubic  yard,  of  which  $2.83  was  for  labor  and  $6. 10  for  top  charges. 

In  driving  tunnels  westward  from  the  Long  Island  shaft, 
the  materials  were  encountered  in  the  following  order:  124 
feet  of  all  rock  section;  125  feet  of  earth  and  rock;  22  feet 
of  all  rock;  56  feet  of  earth  and  rock;  387  feet  of  all  rock  section; 
70  feet  of  earth  and  rock;  and  1333  feet  of  all  earth  section. 
The  rock  was  similar  to  that  in  the  Blackwell's  Island  reef  and 
was  covered  with  sand  and  boulders.  The  soft  ground  was 
of  three  classes.  The  first  was  of  fine  red  sand,  occurring  in 
layers  from  6  to  15  feet  thick.  This  is  the  quicksand  usually 
found  in  deep  foundations  in  New  York  City.  With  surplus 
water  this  sand  is  a  true  quicksand.  When  the  water  is  blown 
out  by  air  pressure  it  is  stable,  stands  up  well  and  is  easy  to 
work.  The  second  material  was  known  as  "  bull's  liver," 
consisting  of  thin  layers  of  blue  clay  and  of  a  very  fine  red  sand. 
The  clay  was  entirely  free  from  sand.  This  was  an  ideal  material 
in  which  to  work  a  shield,  as  it  stood  up  well,  held  the  air  about 
as  well  as  clay  and  was  much  easier  to  work.  The  third  material 
was  a  layer  of  very  fine  open  gray  sand  which  was  encountered 
in  the  top  of  all  the  tunnels  for  about  four  hundred  feet  just 
east  of  Blackwell's  Island  reef. 

The  first  work  in  air  pressure  was  to  remove  the  shield  plug 
closing  the  opening  in  the  side  of  the  shaft.  This  being  done, 
the  shield  was  shoved  through  the  opening  and  excavation 
begun.  The  shields  were  fitted  with  movable  platforms  and  the 
hoods  were  not  placed  until  the  rock  excavation  had  been  com- 
pleted. Shields  had  not  been  extensively  used  in  rock  up  to 
this  time  and  it  was  therefore  necessary  to  develop  methods 
of  operation  by  experience.  When  rock  was  present  under  the 
shields  it  was  required  that  a  bed  of  concrete  be  laid  in  the  form 
of  a  cradle,  upon  which  the  shield  was  moved.  Three  general 
methods  were  used  for  excavating  in  the  all  rock  sections — the 
bottom  heading  method,  the  full  face  method  and  the  center 
heading  method. 


136      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

The  bottom  heading  method  was  the  first  one  tried.  A 
heading  8  by  12  feet  wide  was  driven  on  the  center  line,  the 
bottom  being  at  the  grade  line  of  the  tunnel  floor.  Four  drills 
were  used,  mounted  on  a  column.  The  face  of  the  heading  was 
kept  from  10  to  30  feet  in  advance  of  the  shield.  A  concrete 
cradle,  8  to  10  feet  wide,  was  laid  when  the  heading  had  been 
driven  10  feet.  The  excavation  was  enlarged  to  full  size  as  the 
shield  advanced.  The  drills  were  mounted  in  the  forward 
compartments  of  the  shields,  and  the  sides  and  top  of  the  excava- 
tion were  shot  downward  into  the  heading.  As  the  heading 
was  completely  blocked  by  the  material  blasted  from  the  face, 
work  had  to  be  suspended  until  the  face  had  been  mucked. 

The  bottom  heading  method  was  as  good  as  could  be  devised, 
with  the  shields  equipped  with  two  transverse  bulkheads,  as 
originally  installed.  All  the  muck  had  to  be  taken  from  the 
face  by  hand  and  passed  through  the  chutes  and  doors.  The 
closed  transverse  bulkheads  were  an  obstacle  to  rapid  progress 
in  rock  sections.  These  bulkheads  with  air  locks  were  designed 
in  the  belief  that  it  would  be  necessary  to  maintain  the  full 
air  pressure  in  the  working  compartment  only.  In  the  case  of 
blowouts  it  was  thought  that  some  form  of  bulkhead  that  could 
be  quickly  closed  tight  would  be  required  to  avoid  flooding  the 
tunnel.  From  experience  gained  while  working  in  the  sand  from 
Manhattan  to  the  Blackwell's  Island  reef,  it  was  demonstrated 
that  this  design  was  not  practicable,  and  that  a  bulkhead  closed 
in  the  bottom  was  a  hindrance.  The  bulkheads  were  cut  through 
and  altered  to  permit  of  the  passage  of  cars  through  the  shield. 

To  avoid  blocking  the  tracks  when  blasting  and  to  permit 
working  a  larger  force  of  men  at  the  face,  the  level  of  the  head- 
ing was  raised.  This  reduced  the  quantity  of  rock  to  be  taken 
from  the  top  and  the  bottom  was  taken  out  as  a  bench.  To 
keep  the  tracks  clear  while  blasting,  a  timber  platform  was 
built  from  the  center  floor  of  the  shield.  The  platforms  were 
not  entirely  satisfactory  and  later  the  drills  in  the  heading  were 
turned  upward  and  a  top  bench  also  worked.  So  little  excava- 
tion was  left  in  the  top  that  the  muck  was  allowed  to  fall  in  the 
tracks,  from   which  it  was   quickly   cleared.     This  method  as 


PentiBylv«ma  R.R.  East  River  Tunnels. 


ZE-BOTTOM  ii^mTSHk-^ 

FiG.l 


I  If  i 
iJJ 


LONGITUDINAL  SECTION 
FiG.t; 


iSITION 


••■Earth 


fe  Kock 


CROSS-SICTION    n-D 


ENLARGING  TUNNEL  TO  FULL  SIZE-BOTTOM  HEADIN 


'■t^v^vJa^.^Ja-  >  ^"gy^^rtf^i  iggKwKW* 


ENLARGING  TO  FULL  SIZE.CROWN  BARS  IN  POSITION 


CROSS-SECTION  E-3 
Fio.l 

Methods  of  Excavation,  Pennsylvania  R.R.  Eaal  liiver  Tunnels. 


CROSS  SICTION 


THE  EAST   RIVER  TUNNELS  137 

outlined,  called  the  center  heading  method,  proved  the  most 
satisfactory  for  full  rock  sections. 

Excavation  in  earth  and  rock  was  the  most  difficult  class 
of  work  encountered,  particularly  when  the  rock  was  covered 
with  boulders  and  coarse,  sharp  sand  which  permitted  a  free 
escape  of  air.  Before  removing  the  rock  under  soft  ground 
it  was  necessary  to  excavate  the  latter  in  advance  of  the  shield 
to  a  point  beyond  where  the  rock  was  to  be  disturbed,  and  to 
support  the  top,  sides  and  face  of  the  opening  thus  made.  A 
fixed  hood  attached  to  and  in  advance  of  the  shield  was  designed 
to  support  the  top  and  sides  of  the  excavation.  With  this  fixed 
hood  it  was  necessary  either  to  force  the  hood  into  the  undis- 
turbed material,  the  distance  required,  or  to  excavate  an  opening. 
To  avoid  this  difficulty  sliding  hoods  were  tried  as  an  experiment, 
made  in  segments,  which  were  forced  forward  by  screw  rods 
one  at  a  time  into  the  material  as  far  as  possible.  Enough  mate- 
rial was  then  removed  from  beneath  and  in  front  of  the  segment 
to  free  it  when  it  was  forced  farther  forward.  These  opera- 
tions were  repeated  until  the  section  had  been  extended  far 
enough  for  a  shove.  When  the  shield  was  advanced  the  nuts 
on  the  screw  rods  were  loosened  and  the  hood  telescoped  on  the 
shield.  Owing  to  the  transverse  strains  on  the  hood  section, 
caused  by  the  unequal  relative  movements  of  the  top  and  bottom 
of  the  shield  in  shoving  forward,  this  plan  proved  impracticable. 

Fixed  hoods  were  substituted  for  the  sliding  type  and  poHng 
boards  used  to  support  the  roof  and  sides,  with  breast  boards 
for  the  face.  In  placing  the  poling  and  breasting,  all  voids 
behind  them  were  filled  with  marsh  hay  or  bags  of  sawdust 
or  clay.  To  prevent  loss  of  air  in  open  material  the  joints  between 
the  boards  were  plastered  with  clay  especially  prepared  in  a 
pug  mill  for  this  purpose. 

When  the  rock  face  became  sufficiently  high  and  sound,  a 
bottom  heading  was  driven  some  20  or  30  feet  in  advance  of  the 
shield,  and  the  cradle  placed.  The  remainder  of  the  rock 
face  was  removed  by  firing  top  and  side  rounds  into  the  bottom 
heading  after  the  soft  ground  had  been  excavated.  To  avoid 
a  run  of  material  great  care  was  taken  in  firing  not  to  disturb 


138  SUBWAYS  AND   TUNNELS   OF  NEW  YORK 

the  timbering  on  the  rock  under  the  breast  boards.  In  the 
early  part  of  the  work  when  a  bottom  heading  was  impracticable, 
the  soft  ground  was  first  excavated  as  described  above,  and  the 
rock  was  drilled  by  machines  mounted  on  tripods  and  fired  as  a 
bench.  By  this  plan  no  drilling  could  be  done  until  the  soft 
ground  was  removed.  This  was  called  the  rock  bench  method. 
Later  the  rock  cut  method  was  devised.  Drills  were  set  up  on 
columns  in  the  bottom  compartments  of  the  shields  and  the 
face  drilled  while  work  was  in  progress  in  the  soft  ground  above. 
This  drilling  was  done  either  for  horizontal  or  vertical  cut, 
and  side  and  top  rounds.  The  drill  runners  were  protected 
while  at  work  by  timber  platforms  built  out  from  the  floors 
of  the  compartments  above.  This  plan,  while  not  as  economical 
of  explosive,  saved  the  delay  due  to  drilling  the  bench. 

In  driving  the  tunnels  which  connected  the  river  shafts 
in  Long  Island  City  with  East  Avenue,  a  temporary  shaft  was 
sunk  at  East  Avenue.  This  was  rectangular  in  shape,  built 
of  rough  6  by  12  sheet  piling,  127  by  34  feet.  It  was  braced 
across  by  heavy  timber  and  was  driven  about  28  feet  to  rock 
as  the  excavation  progressed.  Below  this  the  shaft  was  sunk 
in  rock  about  27  feet  without  timbering.  When  the  shaft  was 
down,  bottom  headings  were  started  westward  in  the  tunnels. 
When  these  had  been  driven  about  half  way  to  the  river  shafts, 
soft  ground  was  encountered;  and  as  the  latter  carried  consider- 
able water  it  was  decided  to  use  compressed  air.  Bulkheads 
were  built  in  the  headings  and  with  an  air  pressure  of  about 
15  pounds  the  heading  was  driven  through  the  soft  ground  and 
into  rock  by  ordinary  mining  methods.  The  use  of  compressed 
air  was  then  discontinued. 

West  of  this  soft  ground  the  top  heading  followed  by  a 
bench  was  driven  until  soft  ground  was  again  encountered. 
One  of  the  four  tunnels,  being  higher,  was  more  in  soft  ground. 
At  first  it  was  the  intention  to  delay  this  excavation  until  it 
had  been  well  drained  by  the  bottom  headings  of  the  tunnels 
on  either  side;  later  it  was  decided  to  use  a  shield  without 
compressed  air.  This  shield  had  been  used  in  excavating  the 
stations  of  the   Great  Northern  and  City  tunnel  in  London. 


THE   EAST   RIVER  TUNNELS  139 

It  was  rebuilt,  its  diameter  being  changed  from  24  feet  81-  inches 
to  23  feet  5I  inches.  But  it  proved  too  weak  and  after  it  had 
been  flattened  about  4  inches  and  jacked  up  three  times,  the 
scheme  was  abandoned,  the  shield  removed  and  the  work  con- 
tinued by  the  methods  employed  in  the  other  tunnels.  The 
description  of  operations  in  one  tunnel,  therefore,  will  serve 
for  all. 

From  the  bottom  headings  break-ups  were  started  at  several 
places  in  each  tunnel  where  there  was  ample  cover  of  rock. 
Where  the  roof  was  in  soft  ground  top  headings  were  driven 
from  the  point  of  break-up  and  timbered.  As  soon  as  the  full- 
sized  excavation  was  completed,  the  iron  lining  was  built, 
usually  in  short  lengths.  x\t  a  point  under  the  Long  Island 
Railroad  station  the  tunnels  were  in  soft  ground  and  to  avoid 
disturbance  of  the  surface  a  shield  and  compressed  air  were 
used.  The  shield  was  used  to  drive  three  of  the  tunnels,  but 
during  the  driving  it  was  found  that  the  ground  passed  through 
was  better  than  had  been  anticipated.  There  was  considerable 
clay  in  the  sand  and  after  the  water  had  been  blown  out  by 
compressed  air  it  was  found  to  be  very  stable.  The  fourth 
tunnel  was  timbered  and  driven  under  air  pressure  without 
a  shield. 

When  the  tunnel  was  all  in  good  rock  two  distinct  methods 
were  used.  The  first  was  the  bottom  heading  and  break-up, 
and  the  second  the  top  heading  and  bench  method.  The  bottom 
heading.  13  feet  by  9  feet  high,  having  first  been  driven,  a  break-up 
was  started  by  blasting  down  the  rock  to  form  a  chamber  of 
the  full  height  of  the  tunnel.  A  timber  platform  was  then 
erected  in  the  bottom  heading  and  extended  through  the  break-up 
chamber.  The  plan  was  then  to  drill  the  entire  face  above 
the  top  heading  and  blast  it  down  upon  the  timber  staging. 
In  this  way  the  passage  in  the  bottom  heading  was  not  inter- 
fered with.  The  spoil  was  loaded  into  cars  in  the  bottom 
heading  through  holes  in  the  staging.  This  method  had  the 
advantage  that  the  bottom  heading  could  be  pushed  through 
rapidly,  and  from  it  the  tunnel  could  be  attacked  at  a  number 
of  points  at  one  time.     It  was  found  to  be  more  expensive 


140      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

than  the  top  heading  and  bench  method;  and  as  soon  as  the 
depression  of  the  rock  was  passed,  a  top  heading  about  7  feet 
high  and  roughly  the  segment  of  a  23-foot  circle,  was  driven 
to  the  next  soft  ground  in  each  of  the  tunnels.  The  remainder 
of  the  section  was  taken  out  in  two  benches;  the  first,  about 
4  feet  high,  was  kept  about  15  feet  ahead  of  the  lower  bench, 
which  was  about  1 1  feet  high. 

For  a  length  of  about  2500  feet  of  tunnel  the  roof  was  in 
soft  ground  and  it  was  excavated  in  normal  air  pressure  by 
the  usual  methods  of  mining  and  timbering.  In  the  greater 
part  of  this,  rock  surface  was  well  above  the  middle  of  the 
tunnel.  Starting  from  the  break-up  in  the  all-rock  section, 
when  soft  ground  was  approached  the  top  heading  was  driven 
from  the  rock  into  and  through  the  earth.  This  was  done  by 
the  usual  post,  cap  and  pohng  board  method,  giving  a  heading 
about  7  feet  high  by  6  feet  wide.  The  ground  was  a  running 
sand  with  little  or  no  clay  and  with  considerable  water  in  places. 
All  the  headings  required  side  polings.  The  roof  poling  boards 
were  about  2\  or  3  feet  above  the  outside  limit  of  the  tunnel 
lining. 

The  next  step  was  placing  two  crown  bars,  usually  about 
20  feet  long,  under  the  caps.  Posts  were  then  placed  under 
the  bars,  and  poling  boards  at  right  angles  to  the  axis  of  the 
tunnel  were  driven  out  over  the  bars.  As  these  polings  were 
being  driven  the  side  polings  of  the  original  headings  were 
removed,  and  the  earth  mined  out  to  the  end  of  these  new  trans- 
verse poHngs.  Breast  boards  were  set  on  end  under  the  ends 
of  the  transverse  polings  when  they  had  been  driven  out  to 
their  limit.  Side  bars  were  then  placed  as  far  out  as  possible 
and  supported  on  raking  posts.  These  posts  were  carried  down 
to  rock,  if  it  were  near,  otherwise  a  sill  was  placed  beneath  them. 

A  new  set  of  transverse  polings  was  driven  over  these  side 
bars  and  the  process  was  repeated  until  the  sides  had  been  carried 
down  to  rock,  or  to  the  elevation  of  the  sills  supporting  the 
posts,  which  were  usually  about  4  feet  above  the  axis  of  the 
tunnel.  The  plan  then  was  to  excavate  the  remainder  of  the 
section  and  build    the  iron    lining  in  short  lengths,  gradually 


THE  EAST  RIVER  TUNNELS 


141 


*3aiAup  i^nunp 


142      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

transferring  the  weight  of  the  roof  bars  to  the  iron  lining  as  the 
posts  were  taken  out.  Such  workings  were  in  progress  at  as 
many  as  eight  places  in  one  tunnel  at  one  time. 

The  plan  adopted  in  one  tunnel  for  driving  in  compressed 
air  without  a  shield  through  soft  ground,  while  not  as  rapid, 
proved  to  be  as  cheap  as  the  work  done  by  the  shields.  The 
operation  of  this  scheme  was  as  follows:  Having  the  iron 
built  up  to  the  face  of  the  full-sized  excavation,  a  hole  or  top 
heading  about  3  feet  wide  and  4  or  5  feet  high  was  excavated 
about  10  feet  in  advance.  This  was  done  in  a  few  hours  with- 
out timbering  of  any  kind.  As  soon  as  this  heading  was  ten 
feet  out,  6  by- 12 -inch  pohngs  were  put  up  in  the  roof  with 
the  rear  ends  resting  on  the  iron  lining  and  the  front  ends  on 
the  vertical  breast  boards.  The  heading  was  then  widened  out 
rapidly  and  the  lagging  was  placed  down  to  about  45  degrees 
from  the  crown.  The  forward  ends  of  the  lagging  were  then 
supported  by  a  timber  rib  and  sill.  Protected  by  this  roof, 
the  full  section  was  excavated  and  three  rings  of  iron  lining  were 
built  and  grouted;  and  then  the  whole  process  was  repeated. 


CHAPTER  XVII 

THE  EAST  RIVER   TUNNELS  OF  THE  PENNSYLVANIA  RAILROAD 

(Continued.) 

As  already  stated,  the  specifications  of  the  railroad  company 
required  an  air  compressor  plant  capable  of  supplying  not 
less  than  300,000  cubic  feet  of  free  air  per  hour  at  50  pounds 
pressure  above  normal  atmosphere  to  each  heading,  and  a  reserve 
plant  of  25  per  cent  of  this  capacity.  The  air  compressor 
plants  on  each  side  of  the  river,  installed  by  the  Ingersoll- 
Rand  Company  of  New  York,  met  these  requirements,  having 
a  rated  capacity  of  25,000  cubic  feet  of  free  air  per  minute  or 
an  average  of  5260  cubic  feet  per  minute  per  heading. 

In  tunnels  B,  C  and  D  the  shields  broke  through  rock  sur- 
face in  November  and  December,  1905.  The  air  consumption 
in  the  four  tunnels  exceeded  15,000  cubic  feet,  and  in  tunnel 
D  alone  on  several  occasions  it  exceeded  7000  cubic  feet  per 
minute  for  twenty-four  hours.  Blows  had  been  frequent  and 
it  was  evident  that  a  greater  volume  of  air  would  be  required 
than  was  anticipated  in  order  to  drive  the  four  tunnels  simulta- 
neously in  the  open  material  east  of  the  Manhattan  rock.  Work 
was  accordingly  suspended  on  two  of  the  tunnels  while  the  rated 
capacity  of  the  compressing  plant  was  being  increased  from 
25,000  to  35,000  cubic  feet  of  free  air  per  minute. 

During  one  period  of  the  work  one,  and  sometimes  two, 
tunnels  were  shut  down.  The  consumption  of  air  in  the  tunnels 
from  Manhattan  averaged  more  than  20,000  cubic  feet  per  minute 
for  periods  of  from  30  to  60  days.  It  was  often  more  than  25,000 
cubic  feet  per  minute  for  twenty-four  hours,  with  a  maximum 
of  nearly  29,000  cubic  feet.  On  several  occasions  the  quantity 
supplied  to  a  single  tunnel  averaged  more  than  15,000  cubic 
feet  throughout  a  24-hour  period.  The  greatest  average  for 
twenty-four  hours  was  in  excess  of  19,000  cubic  feet  per  min- 

143 


144  SUBWAYS  AND  TUNNELS   OF  NEW  YORK: 

ute;  but  conditions  were  so  favorable  in  the  other  headings  at  this 
time  that  work  could  be  carried  on  continuously  in  all  of  them. 

The  need  of  driving  all  headings  simultaneously  from  the 
Long  Island  side  was  so  evident  that  it  was  decided  to  increase 
the  rated  capacity  of  the  Long  Island  City  plant  to  45,400 
cubic  feet  of  free  air  per  minute,  which  was  10,400  cubic  feet 
in  excess  of  the  augmented  Manhattan  plant. 

The  earth  encountered  on  emerging  from  the  rock  when 
driving  westward  from  Long  Island  was  far  more  compact  and 
less  permeable  to  air  than  on  the  Manhattan  side.  But  for  a 
distance  of  from  400  to  600  feet  immediately  east  of  the  reef 
a  clean,  open  sand  was  met,  and  while  the  shields  were  passing 
through  this  the  quantity  of  air  suppHed  to  the  four  headings 
was  seldom  less  than  20,000  cubic  feet  per  minute;  it  was 
usually  more  than  25,000  cubic  feet,  with  a  recorded  maximum 
of  33400  cubic  feet.  This  was  a  greater  volume  than  was  ever 
used  on  the  ^Manhattan  side  and  it  was  more  uniformly  distrib- 
uted among  the  several  headings.  In  no  case,  however,  did 
the  air  consumption  per  heading  equal  the  maximum  observed 
on  the  Manhattan  side,  the  largest  on  the  Long  Island  side 
being  12,700  cubic  feet  per  minute  for  twenty-four  hours.  It 
is  to  be  remembered  that  at  one  time  only  two  tunnels  were  in 
progress  in  the  bad  material,  working  eastward  from  Manhattan. 

It  would  seem  that  a  reasonable  compliance  with  the  actual 
needs  on  the  Manhattan  side  would  have  been  an  air  compressing 
plant  of  a  rated  capacity  of  45,400  cubic  feet  per  minute,  and  on 
the  Long  Island  side  one  of  a  capacity  of  35,000  cubic  feet  per 
minute. 

The  total  quantity  of  free  air  compressed  for  the  supply 
of  the  working  chambers  of  the  tunnels  and  the  Long  Island 
caissons  was  34, 109,000,000  cubic  feet.  In  addition  10,615,000,000 
cubic  feet  were  compressed  to  between  80  and  125  pounds  for 
power  purposes,  of  which  at  least  80  per  cent  was  exhausted  in 
the  compressed  air  working  chambers.  The  total  supply  of 
free  air  to  each  heading  while  under  pressure,  therefore,  averaged 
about  3550  cubic  feet  per  minute. 

Investigation   of   the   number  of    blowouts    showing  large 


THE  EAST  RIVER  TUNNELS  145 

losses  of  pressure  and  with  the  relatively  large  reservoir  capacity 
provided  by  the  long  stretch  of  tunnels,  a  maximum  loss  of 
220,000  cubic  feet  of  free  air  was  known  to  occur  in  ten  minutes. 
Of  this  quantity,  however,  probably  30  or  40  per  cent  escaped 
in  the  first  forty-five  seconds,  while  the  remainder  was  a  more 
or  less  steady  loss  up  to  the  time  when  the  supply  could  be 
increased  sufficiently  to  maintain  the  lower  pressure.  Very 
few  blows  showed  losses  approaching  this  in  quantity,  and  in 
this  particular  case  the  inherent  inaccuracies  of  the  observa- 
tions make  the  figures  only  a  rough  approximation. 

A  clay  blanket  covering  the  open  materials  penetrated  by 
the  tunnels  was  essential  throughout  the  work.  The  material 
used  in  this  blanket  amounted  to  283.412  cubic  yards,  of  which 
117,846  cubic  yards  were  removed  from  over  the  completed 
tunnels  and  re-deposited  in  advance  of  the  shields.  A  total 
of  88.059  cubic  yards  of  clay  was  dumped  over  blowouts. 
The  total  cost  of  placing  and  removing  the  clay  blanket  was 
$304,056. 

The  standard  cast-iron  tunnel  lining  was  of  the  usual  tube 
type  23  feet  in  outside  diameter.  The  rings  were  30  inches  wide 
and  were  composed  of  eleven  segments  and  a  key.  The  webs 
of  the  segments  were  i^  inches  thick  in  the  central  portions 
and  increased  to  2f  inches  at  the  flanges  which  were  1 1  inches 
deep  and  machined  on  all  contact  faces.  Bolt  holes  were  cored 
in  the  flanges.  The  segments  weighed  about  2020  pounds 
each  and  the  key  520  pounds.  The  weight  of  the  iron  per  foot 
of  tunnel  was  9102  pounds. 

The  tube  of  iron  rings  was  adapted  to  be  built  in  the  tail 
of  the  shield.  Where  no  shield  was  used,  after  the  excavation 
was  completed  and  all  loose  rock  removed,  timbers  were  fixed 
across  the  tunnels  from  which  semicircular  ribs  were  hung, 
below  which  lagging  was  placed.  The  space  between  this  and 
the  rough  rock  surface  was  filled  with  concrete  forming  a  cradle 
in  which  the  iron  tube  could  be  erected.  At  the  same  time  it 
occupied  a  space  that  would  have  had  to  be  filled  with  grout 
at  a  greater  cost  had  the  shield  been  used.  These  concrete 
cradles  averaged  1.05  cubic  yards  per  foot  of  tunnel  and  cost, 


146 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


Placing  Concrete  in  Pennsylvania  R.R.  East  River  Tunnels, 


Method  of  Grouting  Outside  Iron  Linijg,  Pennsylvania  U.K.  East  River  Tunnels. 


THE  EAST  RIVER  TUNNELS  147 

exclusive  of  material,  $6.70  per  cubic  yard,  of  which  $2.25  was 
for  labor  and  $4.45  top  charges. 

As  soon  as  each  ring  was  erected,  the  space  between  it  and 
the  roof  of  the  excavation  was  filled  with  hand-packed  stone. 
The  interstices  between  the  hand-packed  stones  were  then  filled 
with  i-to-i  grout  of  cement  and  sand  injected  through  the  iron 
lining.  The  hand-packed  stone  averaged  i^  cubic  yards  per 
foot  of  tunnel  and  cost  $2.42  per  cubic  yard,  of  which  $.98  was 
for  labor  and  $1.44  for  top  charges. 

It  was  planned  to  erect  the  iron  lining  with  erectors  of  the 
same  t\^e  as  those  used  in  the  iron  shields,  but  mounted  on 
a  traveling  stage.  There  were  two  erectors,  but  as  the  tunnel 
was  being  worked  at  so  many  points  this  number  was  inadequate 
to  meet  the  requirements.  As  a  result  about  58  per  cent  of  the 
lining  was  done  by  hand.  A  portable  hand  winch  was  used  for 
handling  and  placing  the  segments.  The  cost  of  erecting  by 
hand  was  no  greater  than  by  the  erectors.  This  was  due  to 
the  greater  power  and  plant  charges  against  the  erectors  and 
to  the  fact  that  they  were  not  in  constant  use. 

The  total  amount  of  grout  used  on  the  work  was,  in  set 
volume,  equivalent  to  249,647  barrels  of  i-to-i  Portland  cement 
grout,  of  which  233,647  barrels  were  injected  through  the  iron 
lining.  The  average  was  19.93  barrels  per  lineal  foot  of  tunnel. 
The  cost  of  the  grout  injected  outside  of  the  iron  tunnel  was 
$.93  per  barrel  for  labor  and  S2.77  for  top  charges.  East  of  the 
Long  Island  shaft  the  corresponding  costs  were  $.68  and  $1.63, 
the  difference  being  partly  due  to  the  large  percentage  of 
work  done  in  normal  air. 

Joints  were  at  first  caulked  with  a  mixture  of  iron  filings 
and  sal  ammoniac  in  the  proportions  by  weight  of  400  to  i, 
caulked  by  hand.  Later,  lead  wire  caulked  cold  by  pneumatic 
hammers  was  substituted.  The  average  cost  of  labor  was  S.12 
per  lineal  foot  and  top  charges  $.218.  All  concrete  was  placed 
under  normal  air.  The  cost  of  labor  chargeable  to  concrete 
was  $1.80  per  cubic  yard  and  top  charges  were  $3.92  exclusive 
of  the  cost  of  materials. 

From  Proceedings  of  the  American  Society  of  C.  E.,  October,  1909. 


CHAPTER  XVIII 

THE   BELMONT  TUNNELS 

The  various  tunnel  and  subway  undertakings  which  are 
to  vastly  increase  the  transit  facihties  of  Greater  New  York, 
are  quite  different  from  each  other  in  the  conditions  and  means 
of  construction,  and  each  has  imposed  special  engineering 
problems  to  be  solved.  Not  the  least  interesting  was  the  work 
on  the  Belmont  tunnels  under  the  East  River  which  are  now 
completed,  but  at  the  time  of  writing  are  not  yet  in  actual 
operation. 

The  Belmont  system  includes  a  tunnel  and  subway  over 
three  miles  in  length,  extending  from  Park  Avenue  and  Forty- 
second  Street,  Manhattan  Island,  to  Jackson  Avenue  and 
Fourth  Street,  Long  Island  City.  It  will  afford  easy  and  quick 
transit  between  the  Borough  of  Queens  and  Manhattan  and  will 
probably  connect  with  some  of  the  transit  systems  in  New  York 
City  near  the  Grand  Central  Station.  The  first  shift  was  started 
in  July,  1905  and  work  was  rushed  continuously  and  with  great 
vigor  night  and  day  until  completion.  The  system  consists 
of  two  single-track  parallel  tunnels.  Part  of  the  tubes  are 
horseshoe  shaped,  while  under  the  river  they  are  of  circular 
section  and  built  of  sectional  cast  iron  rings.  The  contractors 
were  the  Degnon  Engineering  and  Construction  Company.  The 
builders  had  an  advantage  as  to  time  of  construction,  in  that 
the  tunnels  could  be  driven  from  four  headings  instead  of  two, 
or,  as  in  the  case  of  the  Cortlandt  Street  tunnel,  from  a  single 
heading. 

For  driving  the  subaqueous  tunnel  from  its  western  end 
and  for  the  construction  of  the  subway  westward  from  Forty- 
second  Street  there  were  two  separate  compressed  air  instal- 
lations, resulting    from    certain    business   arrangements.      The 

148 


THE    P.KI.MONT  TT'NXELS  149 

I)lant  of  the  O'Rourke  Engineering  Company  which  was  sold 
to  the  Degnon  Company  included  the  following  equipment: 
One  Ingersoll-Rand  cross-compound  Corliss  steam,  2-stage  air 
compressor  with  steam  cylinders,  24  and  40  inches  in  diameter, 
air  cylinders  39  and  24  inches,  stroke  48  inches  and  a  free  air 
capacity  of  4147  cubic  feet  per  minute;  one  Ingersoll-Rand 
cross-compound  Corliss  steam,  2-stage  air  compressor  with  steam 


Long  Island  City  Air  Compressor  Plant,  Belmont  Tunnels. 

cylinders  22  and  40  inches,  air  cylinders  38  and  24  inches,  stroke 
42  inches  and  a  free  air  apacity  of  3937  cubic  feet  per  minute. 

The  Degnon  Contracting  Company's  plant  at  the  same 
point  included  three  Ingersoll-Rand  cross-compound  steam, 
duplex  air  compressors  with  steam  cylinders  15  and  28  inches, 
air  cylinders  201  inches,  stroke  16  inches,  a  free  air  capacity 
of  6540  cubic  feet  per  minute  and  a  maximum  air  pressure  of 
50  pounds.  There  was  also  one  Ingersoll-Rand  cross-compound 
steam,  2-stage  air  compressor  with  a  steam  end  identical  with 


150  SUBWAYS  AND  TUNNELS   OF  NEW  YORK 

the  above  machine,  but  with  compounded  air  cyHnders  251 
and  1 61  inches  in  diameter,  a  free  air  capacity  of  1704  cubic 
feet  per  minute  and  air  pressure  100  pounds. 

The  most  interesting  in  some  respects  of  all  the  New  York 
tunnel  plants  was  that  installed  by  the  Degnon  Contracting 
Company  upon  Man-O'-War's  Reef  in  the  middle  of  the  East 
River,  opposite  Forty-second  Street.  The  existence  of  this 
reef  made  possible  the  sinking  of  two  shafts,  giving  four  addi- 
tional working  faces  for  the  two  sub-river  tunnels.  The  first 
thing  to  be  done  was  to  get  floor  space,  as  the  original  area  wrs 
entirely  insufficient.  At  first  a  single  Ingersoll-Rand  straight 
line  compressor  with  a  portable  boiler  was  installed  and  the 
sinking  of  the  two  shafts  was  begun.  The  material  from  these 
shafts  was  used  for  filling  upon  and  around  the  reef  until  a 
sufficient  area  was  secured  for  the  installation  of  the  complete 
plant,  but  with  not  a  square  foot  of  space  to  spare.  The  com- 
pressor room  extended  to  the  water's  edge  on  two  sides  with 
but  a  small  space  on  the  New  York  side;  while  to  the  north 
enough  land  was  made  to  provide  for  the  moving  of  muck 
cars  to  scows  on  either  side. 

The  power  plant  equipment  used  here  included  one  Ingersoll- 
Rand  straight  line,  steam  driven  compressor  with  24-inch 
steam  cylinder,  26i-inch  air  cylinder,  30-inch  stroke  and  a  free 
air  capacity  of  1843  cubic  feet  per  minute.  In  addition  to  this 
steam  driven  unit  there  were  four  electrically  driven,  belted, 
duplex  compressors  built  by  the  Ingersoll-Rand  Company. 
Three  of  these  had  duplex  air.cyhnders  2oi  inches  in  diameter 
by  16-inch  stroke  with  an  aggregate  free  air  capacity  of  6540 
cubic  feet  per  minute.  The  fourth  machine  was  a  2-stage  com- 
pressor with  air  cylinders  25J  and  16^  inches  in  diameter,  16-inch 
stroke  and  a  free  air  capacity  of  1704  cubic  feet  per  minute. 
This  latter  machine  delivered  air  at  100  pounds  pressure  while 
the  three  other  power  driven  units  carried  50  pounds  air  pressure. 
These  motor  driven  units  were  to  run  at  constant  speed,  the  air 
delivery  being  regulated  by  choking  controllers  on  the  intake. 
One  straight  line  steam  driven  compressor  was  included  in 
this  plant,  but  is  not  shown  in  the  illustration.     The  current 


THE   BEI.MOXT  TrXNKLS 


151 


for  the  electric  motors  was  taken  from  a  cable  connecting  with  the 
Manhattan  lines  of  the  Interborough  Company.  The  elevators 
in  the  two  shafts  were  also  driven  by  electric  power  from  the  same 
source.  Locomotive  boilers  supplied  steam  for  the  two  straight 
line  machines,  the  feed  water  being  piped  from  Manhattan. 

While  this  plant,  on  account  of  its  location  and  of  its  for- 
bidding accompanying  conditions,  might  have  been  regarded 
as  more  or  less  an  emergency  plant,  it  must  not  be  thought 


Man-O'-War's  Reef  Air  Compressor  Plant.  Belmont  Tunnels. 

to  have  been  a  wasteful  one.  The  electrically  driven  machines, 
taking  their  current  from  a  service  in  which  the  highest  possible 
economies  are  attained,  and  having  motors  especially  adapted 
to  their  work,  delivered  their  air  at  a  lower  cost  than  the  straight 
line  steam  driven  machines,  notwithstanding  the  fact  that  the 
latter  represented  practice  still  widely  prevalent. 

In  the  Long  Island  City  plant  there  were  in  service  two 
Ingersoll-Rand  cross-compound  steam,  2-stage  air  compressors 


152      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

with  steam  cylinders  15  and  28  inches  in  diameter,  air  cyhn- 
ders  25j  and  i6i  inches,  16-inch  stroke  and  a  free  air  capacity 
of  3408  cubic  feet  per  minute  at  100  pounds  pressure.  There 
were  also  two  Ingersoll-Rand  straight  line,  steam  driven  com- 
pressors, 24  and  261  by  30  inches  in  dimensions,  with  a  free  air 
capacity  of  3686  cubic  feet  per  minute;  and  one  Ingersoll- 
Rand  machine  of  the  same  type,  24  and  241  by  30  inches, 
free  air  capacity  1570  cubic  feet  per  minute.  These  last  three 
units  were  low  pressure  compressors  and  were  supplied  with 
steam  by  Heine  boilers. 

While  the  pneumatic  pressure  maintained  in  the  tunnels 
until  completion  was  always  equal  to,  or  somewhat  in  excess 
of,  the  hydrostatic  pressure  due  to  the  submergence,  there  was 
a  constant  accumulation  of  water  in  the  workings.  While  the 
air  pressure  would  be  in  excess  of  the  water  pressure  at  the  top 
of  the  shield,  it  might  still  be  insufhcient  at  the  bottom;  and 
here  the  water  entered.  This  was  collected  in  temporary 
sumps  in  the  air-locks  from  which  it  was  forced  out  by  air  pres- 
sure through  pipes  to  various  pumping  stations  situated  along 
the  line  of  construction.  There  was  also  a  constant  seeping 
of  water  through  the  joints  where  the  caulking  had  not  been 
completed.  The  sumps  were  situated  where  the  grade  was 
the  lowest  and  at  these  points  the  pumps  were  located,  lifting 
the  water  to  the  surface  or  directly  into  the  river;  or,  in  the 
land  sections,  into  sewers  connecting  with  the  river. 

In  several  places  the  segments  or  wall  plates  were  removed 
and  the  material  forming  the  8-foot  partition  between  the  two 
tubes  was  cut  away  to  provide  sump  chambers  and  to  allow 
room  for  the  pumps. 

Where  the  pumps  were  situated  alongside  the  tunnel  walls 
and  in  the  workings,  no  extra  room  was  required  for  their 
installation,  as  these  pumps  were  all  of  the  Cameron  type, 
with  their  well-known  and  characteristic  lack  of  protuberant 
parts. 

The  Cameron  pumps  were  particularly  well  adapted  for  use 
in  tunnels  or  other  restricted  quarters,  or  in  situations  exposed 
to  flooding,  or  falling  rock  or  debris  from  blasting  or  excavation. 


THE  BELMONT  TUNNELS 


153 


Battery  of  Cameron  Pumps  installed  in   "  Belmont  "   Tunnel,  under  East 
River,  under  Man-O'-War's  Reef. 


They  had  no  outside  valve  gear  or  moving  parts  to  be  deranged 
or  broken  by  passing  cars  or  falHng  material.  They  were  reliable 
under  all  conditions,  and  in  cases  of  sudden  flooding  would  work 
as  well  when  submerged  to  any  depth  as  under  normal  condi- 
tions. In  case  of  accident  or  emergency  they  could  be  run  up 
to  double  their  normal  capacity. 

A  simple  device  was  attached  to  the  pumps  to  keep  the 
exhaust  compressed  air  from  freezing  and  choking  the  passages. 
A  small  pipe  was  connected  from  the  water  discharge  pipe  to 
the  exhaust  openings  of  the  air  operated  cylinder,  and  through 
it  a  f-inch  nozzle  discharged  constantly  when  the  pumps  were 
running.  This  not  only  prevented  freezing,  but  also  had  the 
effect  of  a  muffler  on  the  exhaust.  These  pumps  were  driven 
by  compressed  air,  as  were  also  the  drills  and  the  hoisting  and 
other  machinery  employed. — Frank  Richards,  in  Compressed  Air 
Magazine. 


CHAPTER   XIX 

THE   HUDSOX-MAXHATTAX   TUXXELS 

As  stated  in  an  early  chapter  of  this  book,  De  Witt  C.  Haskins 
began  the  construction  of  a  brick  walled  tunnel  under  the 
Hudson  River  a  third  of  a  century  ago.  One  great  accident 
entaihng  serious  loss  of  life  led  to  legal  and  financial  difficulties 
which  paralyzed  the  undertaking.  In  1902  the  New  York 
and  New  Jerse}'  Railroad  Company  resumed  serious  work  on 
the  tunnel.  In  the  following  year  this  company  was  merged 
with  the  Hudson-Manhattan  Railroad  Company;  and  later 
the  Hudson  Companies  were  formed  to  conduct  the  construc- 
tion and  real  estate  operations  involved.  It  was  estimated 
that  the  entire  project  when  completed  would  cost  $70,000,000. 

The  accompanying  map  of  this  system  makes  clear  its  route 
and  shows  its  ramifications  and  connections.  The  system 
as  a  whole  may  be  considered  as  made  up  of  four  sections.  The 
twin  tubes  from  Hoboken,  X.  J.  near  the  D.  L.  &  W.  terminal, 
under  the  river  to  Sixth  Avenue,  X^ew  York  City,  enter  Man- 
hattan two  blocks  below  Christopher  Street  and  pass  up 
through  Sixth  Avenue  to  Thirty-third  Street  near  the  Penn- 
sylvania Railroad  terminal.  The  south  twin  tunnels,  which 
may  be  called  the  second  section,  were  driven  entirely  from 
the  Jersey  side  of  the  river,  passing  from  the  terminal  of  the 
Pennsylvania  Railroad  in  Jersey  City,  under  the  river  and 
entering  Manhattan  Island  at  Cortlandt  Street. 

At  Jersey  City  a  large  terminal  station  was  hewn  out  of  the 
solid  rock,  85  feet  below  the  present  station  of  the  Pennsylvania 
Railroad.  The  tunnel  station  here  is  150  feet  long  with 
approaches  1000  feet  in  length,  and  is  equipped  with  large  pas- 
senger elevators  to  the  surface.     The  Manhattan    terminal  is 

155 


156  SUBWAYS  AND   TUNNELS   OF  NEW  YORK 

surmounted  by  the  Hudson  Terminal  buildings,  two  of  the 
largest  office  buildings  in  New  York  City. 

The  third  section  is  a  land  tunnel  parallel  with  the  Hudson 
River,  connecting  the  Hoboken  terminal  with  that  in  Jersey 
City  and  commanding  the  passenger  stations  to  four  trunk 
railroad  lines  which  were  formerly  entirely  dependent  on  ferry 
service  for  New  York  connection.  The  fourth  section  is  a  land 
tunnel  running  from  the  Jersey  City  terminal  under  the  Penn- 
sylvania Railroad  Station  toward  Newark.  This  passes  under 
the  most  crowded  portion  of  Jersey  City,  coming  to  the  surface 
at  the  outskirts;  and  the  tunnel  trains  from  this  point  will 
use  the  Pennsylvania  Railroad  tracks  to  the  transfer  station 
at  Harrison  and  thence  to  Newark,  N.J.  It  will  be  noted  that 
more  than  one-half  of  this  entire  system  is  land  tunnel  or,  in 
Sixth  Avenue,  typical  subway  involving  generally  no  unusual 
difficulties.  The  river  work,  however,  presented  unusually 
difficult  engineering  problems.  The  employment  of  compressed 
air  as  a  plenum  and  for  operating  the  drills,  shields  and  other 
mechanism  used  in  construction  was  the  essential  condition 
which  made  it  possible  to  bring  these  tunnels  to  successful 
completion. 

Messrs.  Charles  M.  Jacobs  and  J.  Vipond  Davies  were 
placed  in  charge  of  the  engineering  when  the  project  was  taken 
up  anew  by  the  Hudson  Companies.  The  north  tunnel  had 
then  been  driven  3800  feet  from  the  Jersey  side.  The  shield 
previously  used  in  this  work  was  retained  in  service,  but 
with  necessary  changes  to  adapt  its  use  to  a  spur  of  rock  then 
being  approached  which  would  require  to  be  drilled  and  blasted 
in  advance  of  the  shield.  A  heavy  hood  or  apron  extending 
6  feet  on  the  upper  half  was  added  to  the  shield  to  afford  pro- 
tection to  the  laborers  while  working  in  the  rock.  At  this  point 
work  was  carried  on  under  an  air  pressure  of  33  pounds,  there 
being  14  feet  of  silt  and  65  feet  of  water  above  the  shield.  At 
places  where  blows  occurred  the  river  bed  was  covered  with  a 
clay  blanket  before  operations  could  be  continued. 

In  beginning  the  south  tunnels,  changes  were  made  in  the 
design  of  the  tunnel  and  in  the  mode  of  procedure.     The  size 


THE   HUDSON-MANHATTAN  TUNNELS  157 

was  reduced  to  a  diameter  of  15  feet  3  inches  in  the  clear.  Cast 
plates  bolted  together  insured  a  true  circular  section  and  the 
shield  could  be  manipulated  to  follow  the  alignment.  A 
hydraulic  erector  was  carried  by  the  shield  for  placing  the 
lining  plates  or  sections  in  position  for  bolting. 

The  forward  movement  of  the  shield  was  controlled  by 
hydraulic  jacks  exerting  an  aggregate  thrust  of  2500  tons.  It 
was  found  that  the  shield  could  be  thrust  forward,  displacing 
the  silt  without  excavating  in  front  of  the  shield.  Because  of 
this  quality  in  the  silt  the  cost  of  construction  became  less  than 
ever  before  attained  in  this  class  of  work.  Five  feet  of  advance 
was  considered  good  progress  per  twenty-four  hours  where 
the  material  was  required  to  be  removed  from  in  front  of  the 
shield  before  shoving.  On  the  other  hand,  72  feet  of  progress 
was  made  in  twenty-four  hours  in  the  Cortlandt  Street  tunnels 
where  the  material  was  displaced  by  the  shield. 

In  an  address  by  Mr.  Jacobs,  Chief  Engineer,  before  the 
Yale  Club  of  New  York,  the  following  description  of  some  of  the 
contingencies  of  subaqueous  tunneling  was  given. 

"  At  the  beginning  of  the  work  on  the  south  tube  of  the 
uptown  tunnel,  the  shield  from  the  Hoboken  side  was  being 
advanced  through  the  silt  with  the  shield  doors  closed  so  as  to 
save  the  cost  of  excavation.  While  the  headings  were  still 
under  the  Lackawanna  coal  dock,  the  night  superintendent, 
thinking  that  the  shield  was  moving  \'ery  slowh",  determined 
(contrary  to  orders)  to  open  one  of  the  center  doors  so  as  to  let 
the  mud  come  in  and  so  let  the  shield  go  ahead  faster. 

"  The  silt  shot  in  under  such  pressure  that  it  buried  some 
of  the  workmen  before  they  could  escape;  the  rest  of  the  shift 
got  away  through  the  upper  emergency  lock  which  was  then 
115  feet  away  from  the  shield  face.  The  heading  was  lost,  and 
the  tunnel  between  the  shield  and  the  lock  was  filled  solid  with 
mud.  The  coal  dock  was  crowded  with  shipping  and,  further- 
more, the  Lackawanna  at  that  time  was  not  particularly  favorable 
to  the  tunnel  enterprise,  so  that  it  would  have  been  almost 
impossible  to  get  permission  to  dredge  out  the  bed  of  the  river 
in  front  of  the  shield  so  that  a  diver  could  go  down  and  timber 


158      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

up  the  exterior  opening  of  the  doorway.  The  problem  was 
solved  as  follows: 

"  Two  heavy  mainsails  were  procured  and  a  double  canvas 
cover  about  60  by  40  feet  made  of  them.  Around  the  edges 
were  secured  small  weights  of  pig  iron.  The  canvas  was 
spread  on  a  flat  barge  and  lines  carried  to  fixed  points  to 
hold  the  mainsail  in  position.  The  barge  was  withdrawn  and 
the  mainsail  allowed  to  drop  to  the  bed  of  the  river,  30  feet 
of  it  covering  the  shield  and  the  remaining  30  feet  extending 
out  beyond  the  face  toward  the  middle  of  the  river.  One  of 
the  pipe  valves  in  the  lock  was  then  opened  and  the  mud, 
under  the  direct  pressure  of  the  river,  shot  into  the  tunnel 
westward  of  the  lock  for  40  feet.  It  came  in  a  solid  stream 
for  eight  days  and  nights.  Finally  it  let  up  for  a  few  minutes, 
began  again  and  then  stopped. 

"  A  cavity  had  been  formed  in  the  bed  of  the  river  outside 
the  cutting  edge  of  the  shield  into  which  the  canvas  dropped 
and  was  eventually  drawn  into  the  opening  of  the  doorway 
through  which  the  mud  was  pouring.  A  small  cavity  was 
excavated  in  the  mud-filled  tube  ahead  of  the  lock  and,  the  air 
pressure  being  put  on,  it  immediately  relieved  much  of  the 
strain  on  the  temporary  canvas  cover.  Miners  were  then  able 
to  get  into  the  tunnel  and  dig  out  the  mud.  In  about  nine 
days  the  heading  was  recovered  and  the  door  on  the  inside 
closed. 

''  The  north  tube  is  an  extension  of  an  old  tunnel  abandoned 
some  years  ago.  Within  100  feet  from  the  point  where  the 
shield  stopped  in  the  previous  attempt  was  a  reef  of  rock,  stand- 
ing from  I  to  16  feet  above  the  intended   grade  of  the  tunnel. 

''  Before  the  shield  arrived  at  this  point,  it  was  necessary 
to  build  a  temporary  workshop  in  the  river  ahead  of  the  shield, 
so  as  to  build  on  the  front  of  it  a  steel  apron  under  which  the 
men  could  work  in  drilHng  the  rock  and  blasting  it  out  of  the 
path  of  the  shield.  Above  the  rock  was  soft  silt  and,  above 
that,  from  60  to  65  feet  of  water.  It  was  expected  that  in  blast- 
ing the  rock  with  so  slight  a  cover,  and  with  such  a  heavy  water 
pressure,  the  heading  would  probably  be  blown  out. 


THE  HUDSON-MANHATTAN   TUNNELS  159 

"  Clay  loaded  on  barges  was,  therefore,  always  held  in 
readiness  to  be  dumped  into  any  such  blowout.  After  a  few 
weeks  the  expected  blowout  occurred  and  the  900  feet  of  tunnel 
from  lock  to  heading  was  flooded.  The  men  at  work  escaped. 
The  clay  scows  were  immediately  brought  over  the  blowout 
and  dumped,  thus  blocking  the  hole.  The  water  was  pumped 
out  into  the  western  workings,  and  within  eleven  hours  men 
were  able  to  reach  the  headings  on  a  small  raft.  No  damages 
were  found  and  work  was  soon  again  under  way.  In  all,  only 
twenty-one  hours  of  time  were  lost.  There  were  two  more 
blowouts  while  the  tunnel  was  being  built  across  the  700  feet 
of  reef,  and  in  each  case  they  were  similarly  dealt  with. 

"  Finally,  however,  there  was  a  problem  which  could  not  be 
dealt  with  by  dropping  these  clay  blankets.  At  the  extreme 
eastern  end  of  the  reef  the  rock  rose  about  16  feet  above  the 
bottom  of  the  cutting  edge  of  the  shield.  The  tunnel  at  this 
point  is  so  near  the  bottom  of  the  river  that  the  clay  was  almost 
fluid  and  continually  slipped  into  the  pockets  of  the  shield, 
so  that  the  men  could  not  get  out  underneath  the  apron  to 
drill  the  rock.  Scow  after  scow  was  dumped  but  the  clay  would 
not  hold. 

''  Finally,  blow-pipe  flames,  fed  from  two  tanks  of  kerosene, 
were  directed  against  the  exposed  clay  until  it  was  indurated, 
so  as  to  hold  its  position  while  the  men  drilled  the  rock.  The 
blow-pipe  process  took  eight  hours,  during  which  time  streams 
of  water  were  continually  played  on  the  shield  structure  to  pre- 
vent it  being  damaged  by  the  high  temperature.  This  is  probably 
the  first  time  that  man  has  made  brick  in  the  bottom  of  a  river." 


CHAPTER  XX 

THE   HUDSON-MANHATTAN   TUNNELS     {Continued) 

Wherever  work  was  executed  by  open-cut  methods  the 
structure  was  waterproofed  with  fabric  and  pitch  apphed  in 
the  usual  manner,  making  a  complete  envelope  around  it. 
As  the  greatest  part  of  this  work,  however,  was  executed 
by  tunnel  methods  this  manner  of  waterproofing  was  not 
feasible,  except  in  small  portions  of  the  work.  The  method 
adopted,  therefore,  was  invariably  to  grout  with  Portland 
cement  in  the  rear  of  the  plate  lining  or  concrete  lining, 
and  in  the  majority  of  cases  this  application  answered  the 
purpose  of  making  the  tunnels  perfectly  watertight.  Owing 
to  the  impervi  ousness  of  neat  cement  this  was  the  only  water 
proofing  adopted  on  the  coffer-dam  walls  of  the  Church  Street 
terminal  and  approaches. 

In  the  iron-lined  sections  of  tunnel  all  joints  of  the  plate 
segments  were  first  grummetted  on  the  bolts  with  flax  and  red 
lead  under  the  bolt  washers,  and  caulking  spaces  between  the 
joints  of  the  plate  lining  were  first  caulked  with  a  thread  of  lead 
wire,  followed  up  and  supported  with  rust  joint  cement.  Through- 
out the  concrete  work,  waterproofing  was  done  by  plastering 
the  internal  and  exposed  surface  with  one  of  the  usual  types 
of  waterproofing  compounds  mixed  with  neat  Portland  cement 
and  applied  with  a  trowel,  this  method  answering  admirably 
in  a  majority  of  cases.  At  the  same  time,  in  persistent  leaks, 
it  was  found  necessary  to  cut  right  back  into  the  concrete  and 
expose  the  voids  and  then  reconstruct  such  portion  of  concrete 
with  a  rich  mixture  of  cement.  As  a  general  rule,  for  water- 
proofing of  concrete  work  a  rich  mixture  of  cement  in  the  con- 
crete with  thorough  and  efficient  ramming  answered  the  pur- 
pose and  constituted  the  only  waterproofing  used. 

160 


THE   HUDSON-MANHATTAN   TUNNELS 


101 


Generally  speaking,  the  standard  track  throughout  all  the 
lines  of  the  company  consists  of  white  oak  tiesjaid  in  broken 
trap  rock  ballast  on  a  flat  surface  of  concrete  forming  the  invert. 
This  concrete  invert  fills  the  flanges  between  the  plates  in  the 
tube  tunnels  and  a  drain  is  formed  with  a  reinforced  concrete 
slab  over  the  same  along  the  center  line  of  the  tunnel,  which 
provides  efficient  drainage  of  the  tunnel. 


Interior  of  Hudson-Manhattan  Tunnel. 

The  rails  are  85-pound  A.S.C.E.  section  with  continuous 
rail  joints,  and  all  rails  are  attached  to  the  ties  with  screw  spikes 
of  special  design  for  this  company's  work.  Goldie  tie  plates  are 
used  throughout,  the  plates  being  put  on  the  ties  under  hydraulic 
pressure  before  the  ties  are  sent  into  the  tunnels,  the  plates 
being  put  into  exact  template  spacing.  Holes  in  the  ties  for 
the  screw  spikes  were  bored  with  a  pneumatic  auger  before  the 
ties  were  taken  into  the  tunnels,  and  the  screw  spikes   put   in 


162      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

place  and  driven  with  a  pneumatic  screw  driver  which  proved 
very  rapid  in  operation  and  of  great  efhciency.  This  tool  was 
designed  by  ofl&cers  of  the  company  for  the  particular  use  to 
which  it  was  put. 

All  the  rail  used  in  the  downtown  tunnels  has  been  0.90 
per  cent,  carbon  manufactured  by  the  open  hearth  process  by 
the  Bethlehem  Steel  Company;  and  on  heavy  curves  either 
chrome  nickel  or  manganese  steel  rail  w^as  used,  according  to 
the  radius  of  curvature. 

The  contact  (third)  rail  is  of  special  type,  designed  by 
L.  B.  Stillwell,  the  company's  consulting  electrical  engineer. 
This  rail  is  carried  on  heavy  porcelain  insulators  and  secured 
by  pressed  steel  brackets  to  long  ties  spaced  about  10  feet  apart. 
The  contact  rail  is  protected  by  an  overhanging  board  of  Aus- 
tralian jarrah  wood. 

At  heavy  curves  and  in  the  downtown  terminal,  as  well  as 
at  special  points  where  reinforcing  was  executed,  the  track  was 
laid  in  solid  concrete. 

Guard  rails  are  installed  on  all  curves  of  less  than  750  feet 
radius,  these  rails  being  100-pound  section  A.S.C.E.  and  ts 
inches  higher  than  the  running  rail.  All  frogs  and  switches 
are  of  manganese  steel. 

In  Jersey  City  and  Hoboken  where  the  various  tunnels  of 
the  several  routes  make  connections  between  Jersey  City, 
Hoboken  and  uptown  New  York,  the  elimination  of  grade  cross- 
ings was  essential  to  the  design  of  the  work,  and  to  meet  these 
conditions  the  tunnels  were  superimposed.  This  operation 
necessitated  the  construction  of  junctions  in  the  tunnels,  all  of 
which,  unfortunately,  came  at  locations  where  the  construction 
would  be  in  loose  sand  or  other  soft  foundation  in  which  grave 
difficulties  would  have  been  involved  in  making  the  enlarge- 
ments entirely  by  underground  methods. 

The  enlargement  at  the  junction  of  Sixth  A\  enue  and  Ninth 
Street  was  carried  out  entirely  by  underground  methods  on 
account  of  the  conditions  of  traffic  on  the  streets  above,  which 
would  have  made  open-cut  methods  very  difficult  and  have 
caused  grave  inconvenience  to  the  public.     This  junction  was 


Construction  of  Tunnel  Cross-Omr  Iludson-Mauhattan  Tunnels. 


THE   HUDSON-MANHATTAX  TUNNELS  163 

constructed  in  sand  formation  overlying  the  roc'k,  and^as  the- 
location  was  in  part  on  the  site  of  a  former  creQk  there  was  a/ 
good  deal  of  quicksand  present  to  be  taken  care  of.  The  entire 
work  therefore,  had  to  be  executed  under  air  pressure.  At 
this  point  the  shields  in  the  two  diverging  lines  were  carried 
through  continuously,  forming  the  external  lines  of  the  enlarge- 
ment; and  these  tubes  so  constructed  were  used  to  brace  from, 
in  constructing  the  enlargement. 

Sections  of  lining  plates  were  take  out  from  the  sides  of 
these  tubes  and  tunneling  carried  on  between  the  tubes  for 
the  insertion  of  the  heavy  timbering  put  in  place  to  carry  the 
roof,  maintaining  the  breast  throughout  and  carrying  the  work 
on  in  section  lengths.  In  this  way  excavation  was  carried  on 
and  the  arch  forming  the  permanent  lining  put  in  place  in  short 
lengths  but  of  the  full  structure  width,  having  in  part  a  clear 
span  of  60  feet.  This  work  was  executed  with  only  a  very 
slight  settlement  of  the  surface  of  the  ground.  At  the  same 
time  columns  of  the  elevated  railway  structure  overhead  were 
supported  by  long  girders  wedged  to  brackets  riveted  to  the 
columns  and  constantly  watched  to  take  up  any  settlement 
which  might  occur.  This  method  of  underground  enlargement 
(see  page  156)  was  necessarily  very  expensive,  and  to  execute 
similar  work  in  the  three  different  sites  on  the  Jersey  side,  each 
of  which  was  of  greater  dimensions  than  the  enlargement  at 
Sixth  Avenue  and  Ninth  Street,  made  a  careful  detail  study  of 
the  possibilities  desirable. 

In  Jersey  City,  fortunately,  the  three  junction  enlarge- 
ments involved  came  below  properties  occupied  by  the  Delaware, 
Lackawanna  &  Western  Railroad  and  the  Erie  Railroad  for  yard 
purposes;  and  by  arrangement  with  these  companies  the  surface 
of  the  ground  was  occupied  for  the  purpose  of  carrying  on  the 
work.     In  all  these  cases  the  foundations  could  be  carried  to  rock. 

These  enlargements  were  made  by  caissons  sunk  from  the 
surface.  It  was  proposed  to  use  concrete  lined  steel  caissons 
but  owing  to  the  high  cost  and  the  time  required  for  delivery 
of  the  steel,  a  reinforced  concrete  design  was  adopted  which 
permitted  the  immediate  commencement  of  work  and  at  a  much 


164 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


lower  cost  for  the  caisson.  Three  caissons  fitted  with  locks  and 
other  necessary  equipment  were  built  on  the  ground  and  sunk 
from  the  surface,  as  in  bridge  pier  practice.  Where  the  tunnel 
tubes  were  to  enter  the  caissons,  concrete  dummy  drum  heads 
were  built,  which  were  removed  when  the  proper  elevation  was 


Arrangement  of  Branch  Tunnels  and  Cross-over  on  New  Jersey  Side, 
Hudson-Manhattan  Tunnels. 

reached;  and  shields  were  erected  for  the  commencement 
of  the  tunnels  from  the  caissons.  In  other  cases  shields  drawn 
from  other  points  were  aligned  to  connect  at  the  drum  heads 
where  the  points  were  sealed  with  the  tunnel  lining  before 
removing  the  drum  heads. 


THE  HUDSON-MANHATTAN  TUNNELS  165 

The  sizes  of  caisson  Nos.  i  and  2  were  23  feet  5^  inches  to 
45  feet  8  inches  in  width  by  loi  feet  2  inches  in  length  by  51 
feet  in  height.  Caisson  No.  3  was  106  feet  long,  45  feet  wide  and 
43  feet  11^  inches  high.  This  caisson  was  arranged  with  eight 
tunnels,  as  follows:  At  the  north  end,  two  superimposed  to  and 
from  Hoboken,  and  two  superimposed  to  and  from  New  York, 
and  on  the  south  end  two  superimposed  tunnels  to  and  from 
New  Jersey  and  two  superimposed  tunnels  to  be  used  in  the 
future  when  connection  is  made  with  the  Erie  tracks.  The 
caisson  was  sunk  85  feet  below  tide  level.  Its  total  weight 
was  about  10,000  tons.* 

Perhaps  the  greatest  feat  in  construction  was  the  building 
of  the  tunnels  at  the  intersection  of  Christopher  Street,  Ninth 
Street  and  Sixth  Avenue,  Manhattan.  From  this  point  two 
tunnels  run  east  under  Ninth  Street  and  two  north  under  Sixth 
Avenue.  Here  there  was  the  elevated  railway  overhead,  the 
Metropolitan  Street  Railway  lines  on  the  street  surface,  and 
buildings  on  each  side  of  the  street.  This  made  the  problem 
similar  to  the  intersections  in  Hoboken,  except  that  in  this  case 
the  sinking  of  caissons  was  out  of  the  question. 

To  accommodate  two  tubes  coming  up  from  the  south  and 
the  four  diverging  to  the  east  and  north,  it  was  necessary  to 
build  an  arch  of  which  the  maximum  width  was  68  feet.  The 
work  was  all  in  running  sand  and  of  necessity  was  done  under 
air  pressure.  Two  iron-lined  tunnels  were  run  through  this 
intersection  first,  and  the  side  walls  then  built  in.  Openings 
were  then  made  at  the  tops  of  the  tunnels  and  timbering  or 
sheathing  was  carried  up  so  that  sufficiently  heavy  false  work 
could  be  put  in  for  springing  the  arch.  After  the  arch  was 
completed  the  two  temporary  tunnels  were  taken  out.  This 
work  required  the  greatest  ingenuity  and  care,  for  at  least  eight 
weeks.  Any  accident  to  the  timbering,  any  loss  of  the  necessary 
air  pressure  or  any  carelessness  of  the  men,  would  have  undoubt- 
edly caused  a  cave-in;  and  the  elevated  structure  and  the 
surface  lines,  together  with  the  streets  and  the  buildings  on 
each  side,  would  have  fallen  into  the  excavation.     Every  square 

*  J.  Vipond  Davies,  in  Railroad  Age  Gazelle. 


166      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

inch  of  the  treacherous  ground  had  to  be  protected  by  wooden 
sheathing  the  moment  it  was  exposed;  otherwise  the  vibration 
of  the  passing  trains  above  would  start  the  sand  running.  This 
part  of  the  work  was  the  last  of  the  excavation  necessary  for 
opening  the  railroad  to  traffic,  and  although  it  was  early  in 
December  when  the  spring  of  this  large  arch  was  under  way, 
it  was  finished  so  that  trains  could  be  operated  on  February  lo, 
1908.* 

It  is  interesting  to  note  that  the  original  Ingersoll  air  com- 
pressor installed  at  the  Hoboken  end  of  the  first  tunnel  in  1880 
was  continued  in  service  until  the  completion  of  the  tunnels. 
This  compressor  was  overhauled  in  1890  and  is  rated  as  an 
Ingersoll  Class  "  A  "  with  cylinders  20  inches  and  201  inches 
by  30-inch  stroke,  free  air  capacity  1098  cubic  feet  per  minute. 
The  other  compressors  comprising  the  plants  of  the  three  power 
houses  responsible  for  the  tunnel  work  of  the  Hudson  Com- 
panies all  belong  to  the  same  family.  Besides  the  compressor 
mentioned,  the  Hoboken  plant  included  two  Class  "  A  "  com- 
pressors, 22  and  26^  by  24-inch  stroke,  free  ait  capacity  3686 
cubic  feet  per  minute;  and  one  duplex  Class  "  H  "  IngersoU- 
Rand  machine,  16  and  201  by  16-inch  stroke,  free  air  capacity 
2178  cubic  feet  per  minute. 

The  Morton  Street  plant  at  the  Manhattan  end  of  the  same 
tunnels  comprised  one  duplex  Ingersoll-Rand  compressor, 
22  and  22^  by  24-inch  stroke,  free  air  capacity  2640  cubic  feet 
per  minute;  one  Ingersoll-Rand  Class  "  A  "  22  and  22^  by  24- 
inch,  free  air  capacity  1320  cubic  feet  per  minute;  one  20  and 
22^  by  24-inch,  free  air  capacity  1320  cubic  feet  per  minute; 
and  one  16  and  i6i  by  18-inch,  free  air  capacity  698  cubic  feet 
per  minute. 

At  the  Jersey  City  plant  opposite  Cortlandt  Street  the 
machines  were  three  Ingersoll-Rand  Class  "  H  "  cross-com- 
pound steam,  2-stage  air  compressors  for  high  pressure  air, 
and  three  Ingersoll-Rand  Class  "  H  "  cross-compound  steam, 
duplex  single-stage  air  for  the  low  pressure  air.  The  former 
were  14-  and  28-inch  steam  and  241  and  i4i-inch  air,  by  16-inch 

*  From  paper  b\^  Charles  M.  Jacobs. 


THE   HUDSOX-MAXHATTAX  TUXXKLS  1G7 

Stroke,  free  air  capacity  4170  cubic  feet  per  minute;  and  the 
latter  of  the  same  steam  cylinder  dimensions  with  air  cylinders 
22^  by  16-inch  stroke,  free  air  capacity  7920  cubic  feet  per 
minute.* 

The  Cameron  sinking  pump  was  used  almost  exclusively 
for  taking  care  of  the  drainage  water  in  the  excavation  of  the 
Sixth  Avenue  subway.  This  pump  is  very  light,  compact  and 
readily  handled  and  was  suspended  on  chains  while  in  opera- 
tion. For  its  purpose  as  a  sinking  pump  it  is  particularly 
well  adapted  to  care  for  water  carrying  a  large  proportion  of 
sand  or  sediment,  as  the  water  flows  steadily  in  one  direction, 
and  is  not  retarded  in  its  passage  through  the  valves,  which 
have  large  openings.  These  qualities  permit  of  a  comparatively 
high  speed  of  the  moving  parts,  and  of  a  consequently  large 
quantity  of  water  discharged. 

The  weight  of  the  machine  is  reduced  by  discarding  the 
valve  chest  and  air  chamber,  as  the  valves  are  in  the  lower 
cylinder  and  plunger,  and  the  upper  part  of  the  plunger  performs 
the  functions  of  an  air  chamber.  The  construction  of  the  water 
end  is  very  simple.  All  valves  are  readily  accessible  for  inspec- 
tion, but  as  the  flow  of  water  is  continuously  in  one  direction, 
the  accumulation  of  sediment  or  sand  around  the  valves  is  pre- 
vented. This  prevention  of  the  obstruction  of  the  water  valves 
eliminates  the  most  common  cause  of  the  pump  troubles  experi- 
enced in  sinking  pumps. 

*  From  Compressed  Air  Magazine. 


CHAPTER   XXI. 

THE  HUDSON  TERMINAL  STATION  OF  THE  HUDSON-MANHATTAN 

TUNNELS 

The  provision  for  crossing  the  Hudson  for  the  suburban 
population  resident  in  New  Jersey  has  heretofore  been  solely 
by  ferry.  This  means  of  conveyance,  requiring  the  transfer 
of  passengers  at  each  side  of  the  river,  is  necessarily  slow,  due 
to  the  loading,  starting,  entering  ferry  slips  and  unloading,  these 
delays  being  increased  in  case  of  fog  or  storm,  or  under  winter 
conditions  where  the  slips  are  jammed  with  ice.  The  ferries 
carry  about  120,000,000  passengers  per  annum. 

Excepting  the  New  York  Central  &  Hudson  River  Railroad, 
and  the  New  York,  New  Haven  and  Hartford,  all  the  main 
railway  lines  terminate  on  the  west  bank  of  the  Hudson  and  are 
cut  off  from  direct  connection  with  New  York 

A  tunnel  connecting  New  York  and  the  west  shore  was 
first  practically  considered  in  1873,  when  the  Hudson  River 
Tunnel  Company  was  organized,  and  laid  plans  for  a  line  from 
a  point  at  the  foot  of  Fifteenth  Street,  Jersey  City,  under 
the  Hudson  to  a  point  in  Washington  Square,  New  York 
City.  This  scheme  was  for  a  steam  road  with  its  terminal 
in  Washington  Square,  the  then  resident  district.  The  pro- 
nounced movement  westward  has  necessitated  the  situation 
of  the  terminals  in  other  sections. 

The  center  of  greatest  concentration  in  Manhattan  is  south 
of  the  City  Hall,  and  in  locating  lines  for  a  tunnel  road  the 
problem  presented  was:  First,  to  locate  close  to  Broadway 
and,  second,  to  obtain  a  location  where  the  cost  of  the  site 
would  not  be  prohibitive.  It  was  undesirable  to  cross  Broad- 
way, as  the  east  side  of  that  thoroughfare  is  of  no  greater  value 
for  handling  passengers  than  the  west  side  at  an  equal  distance 

168 


TIIK   HUDSON  TERMINAL  STATION  169 

from  Broadway,  while  the  cost  and  difficulties  of  caring  for  the 
old  buildings  and  their  foundations  would  have  enormously 
increased  the  costs  and  hazards  of  tunnel  building;  and,  in 
addition,  the  connections  with  other  city  lines  are  better  west 
of  Broadway. 

The  scheme  of  operating  the  Jersey  tunnels  and  the  uptown 
lines  fixed  the  train  lengths  at  eight  cars,  each  482  feet  long, 
requiring  a  station  track  388  feet  long  and  platform  lengths  on 
a  tangent  of  about  350  feet. 

The  small  area  of  land  required  for  the  underground  terminal 
was  very  costly.  The  average  price  was,  $40.00  to  $45.00  per 
square  foot,  and  in  addition  there  were  the  payments  under 
the  franchise  provisions  for  lease  and  use  in  perpetuity  of  the 
underground  space  of  the  adjacent  streets.  The  original  idea 
was  to  construct  a  railroad  station  with  a  simple  shed  cover 
over  the  area  at  the  street  level;  but  owing  to  the  unremunera- 
tive  conditions  of  this  plan,  the  investment  being  about 
$3,000,000,  it  was  decided  to  improve  the  property  by  the 
erection  of  an  office  building  that  would  yield  an  income. 

The  location  adopted  for  the  railroad  was  by  a  line  from 
Jersey  City  eastward  to  the  foot  of  Cortlandt  Street,  under 
Cortlandt  Street  to  the  private  property  at  Church  Street 
(the  next  street  west  of  and  parallel  to  Broadway);  thence 
due  north  under  this  property  and  crossing  under  Dey  Street 
to  Fulton  Street  (420  feet  between  the  north  line  of  Cortlandt 
Street  and  south  line  of  Fulton  Street);  thence  turning  west 
under  Fulton  Street  and  again  crossing  the  Hudson  River 
to  Jersey  City.  The  width  of  the  station  site  averages  180 
feet,  and,  including  the  widths  of  Cortlandt  and  Fulton  streets, 
the  length  north  and  south  is  530  feet. 

The  elevation  of  the  tracks  in  the  station  was  determined 
(subject  to  the  limitations  of  the  Rapid  Transit  Railroad  Com- 
missioners) as  1 1.7  feet  below  mean  sea  level,  or  at  a  depth  of 
36.86  feet  below  the  street  surface  at  Church  and  Dey  streets; 
and  this  depth  was  altogether  too  great  for  the  movements  of 
passengers  up  and  down  without  an  intermediate  landing. 
For   railroad   operation,  the   shorter   the   movement   vertically 


170      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

or  horizontally  between  the  concourse  or  distributing  floor 
and  the  cars,  the  better;  and  as  the  clearance  needed  for  the 
cars  was  only  12  feet  6  inches  above  top  of  rail,  and  the  floor 
depth  required  was  only  24  inches,  a  grand  concourse  was  laid 
out  at  an  elevation  of  4.33  feet  above  mean  sea  level.  In  this 
case  there  was  an  added  advantage,  as  at  this  level  the  concourse 
could  be  constructed  continuous  under  Dey  Street  and  prac- 
tically over  the  entire  area  of  the  station  site.  The  only  necessary 
function,  therefore,  of  the  street  level  in  connection  with  the 
railroad  station  was  to  provide  adequate  access  and  egress  for 
passengers,  well  distributed,  to  the  concourse  floor;  and  with 
that  exception  the  entire  surface  area  was  available  as  part  of 
the  office  building  now  developed. 

The  provision  of  platforms,  stairways  and  openings  had 
next  to  be  considered.  To  do  this  intelligently  it  was  necessary 
to  work  back  from  the  ultimate  carrying  capacity  of  the  tunnels. 
The  capacity  of  each  pair  of  tunnels  is  one  trainload  of  800 
persons  on  a  headway  of  90  seconds,  or,  say  530  persons  per 
minute;  and  this  number  either  arriving  or  leaving  at  times 
of  maximum  movement  in  one  direction,  as  the  reverse  move- 
ment is  always  comparatively  light.  Two  terminal  station 
tracks  will  easily  take  care  of  this  service,  allowing  three  minutes 
for  the  train  to  enter  and  stand  in  the  station.  As  there  are  two 
pairs  of  tunnels  provided  for  the  future  (one  pair  of  which  is 
now  in  operation),  the  station  was  laid  out  with  four  operating 
tracks,  and  an  additional  track,  allowing  only  for  unloading 
passengers,  for  car  inspection  and  for  storing  disabled  trains. 
The  unloading  platform  widths  and  areas  need  to  be  sufficient 
to  hold  only  such  part  of  the  trainload  as  would  not  have  passed 
onto  the  stairs  when  the  last  portion  of  the  train  load  has  dis- 
charged; and  obviously  a  floor  area  equal  to  the  train  itself 
is  more  than  adequate  providing  there  is  no  undue  congestion 
on  the  stairs.  In  order  to  load  a  train  promptly  the  loading 
platforms  should  have  sufficient  area  for  a  trainload  of  passengers 
to  stand  without  undue  crowding,  largely  grouped  along  the 
edges  at  the  points  where  the  car  doors  come  when  the  train 
stops,  with  sufficient  space  in  addition  to  permit  a  free  passage 


CORTLANOT  STREET 


FULTON  STREET 

Foundation  and  Track  Arrangement,  Hudson  Terminal  Statif 


THE   HUDSON  TERMINAL   STATION  171 

through  the  crowd  being  maintained.  The  width  should  be 
greater  than  that  of  the  unloading  platforms  and  should  not 
be  less  than  twice  the  width  of  the  trains.  Alternating  the 
platforms  as  before  mentioned  and  thereby  maintaining  one- 
way movement,  permits  this.  The  platforms  as  finally  arranged 
are  as  follows: 

Along  the  Church  Street  side,  an  unloading  platform  iij 
feet  wide  serving  one  track;  area  5200  square  feet. 

Between  tracks  Nos.  i  and  2,  a  double  loading  platform 
22  feet  wide;  area  900D  square  feet. 

Between  tracks  Nos.  2  and  3,  a  double  unloading  platform 
22  feet  wide  serving  two  tracks;  area  9300  square  feet. 

Between  tracks  Nos.  3  and  4,  a  double  loading  platform 
22  feet  wide  serving  two  tracks;  area  9300  square  feet. 

Between  tracks  Nos.  4  and  5,  a  single  unloading  platform, 
13  feet  wide,  serving  No.  5  track  only  in  emergency  and  being 
regular  only  for  No.  4  track;   area  5400  square  feet. 

To  ascertain  the  necessities  in  respect  of  stairs  and  passages, 
count  of  actual  movement  of  traffic  at  congested  points  in  New 
York  was  made,  notably  at  the  Brooklyn  Bridge.  In  a  straight 
passage  of  ample  width,  the  "  rush  hour  "  New  York  crowd  moves 
at  a  rate  of  300  feet  per  minute,  walking  with  a  step  averaging 
30  inches.  There  is  only  a  small  reduction  in  this  speed  on 
ramps  of,  say,  not  over  10  per  cent  grade.  At  this  rate  each 
person  averages  about  10  square  feet  of  space  occupied  and  the 
movement  discharges  about  30  persons  per  foot  of  width  of  pas- 
sage. If  the  passageway  becomes  too  congested,  the  space 
occupied  per  person  reduces  and  the  speed  of  movement  also 
reduces,  but  the  number  discharged  remains  about  the  same, 
thirty  per  minute.  Any  contrary  movement  in  a  broad  passage 
reduces  the  movement  rather  more  than  the  relative  space 
occupied  in  multiples  of,  say,  30  inches  per  person;  but  in 
narrow  passages  the  relative  reduction  is  much  greater,  not- 
withstanding that  persons  crowd  into  smaller  space,  not  over 
24  inches  in  width. 

A  crowd  moving  freely  upward  on  stairs  takes  about  the 
same  number  of  steps  per  minute,  say  120,  but  advances  only 


172      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

about  12  inches  horizontally  instead  of  30  inches.  Upstairs 
movement  is  much  more  dense  than  downstairs,  but  correspond- 
ingly slower.  We  have  counted  discharge  on  stairs  of  24  persons 
per  foot  of  width  per  minute  moving  upward,  but  never  more 
than  18  per  foot  of  width  moving  downward.  There  does 
not  appear  much  difference  in  discharging  rate  on  stairs  above 
4  feet  wide  if  the  movement  is  all  in  one  direction;  but  stairs 
of  all  widths  (particularly  below  8  feet  wide)  are  seriously 
impeded  by  any  contrary  movement  even  when  only  four  or 
five  persons  per  minute  are  moving  in  the  direction  reverse  to 
the  heavy  traffic.  Generally,  for  stairs  above  4  feet  in  width, 
all  movement  in  one  direction,  actual  count  indicates: 

Upward — Maximum,  20  persons  per  foot  of  width  of  stairs 
per  minute.  Average  for  ordinarily  free-moving  crowds,  15  per 
minute. 

Downward — Maximum,  18  persons  per  foot  of  width  of 
stairs  per  minute.  Average  for  ordinarily  free-moving  crowds, 
13  per  minute. 

In  case  of  any  contrary  movement  it  is  most  important 
to  force  the  people  to  a  right-hand  direction  of  movement,  and 
speaking  generally  no  stairs  serving  traffic  in  contrary  directions 
for  railroad  service  should  be  permitted  to  be  installed  of  less 
than  5  feet  clear  width. 

In  unloading  railroad  trains  in  rapid  transit  service,  it  is 
very  important  to  distribute  passengers  as  quickly  as  possible, 
particularly  in  discharge;  and,  in  such  a  problem  as  ours,  to 
get  them  off  the  track  platforms  as  rapidly  as  possible  and 
with  the  least  amount  of  walking  along  the  platforms,  allowing 
them  the  more  easily  to  freely  distrubute  themselves  on  the 
great  concourse  floor.  In  a  full  train  there  are,  say,  twenty 
door  openings  in  the  train,  all  simultaneously  discharging 
practically  a  single  line  of  persons.  Therefore,  we  located 
stairways  on  all  the  unloading  platforms  in  tandem,  six  stairs 
to  each,  distributed  as  nearly  uniformly  along  the  platform 
lengths  as  possible.  No.  i  platform  has  an  aggregate  of  26- 
foot  stairs  to  discharge  at  the  rate  of  800  persons  in  a  3-minute 
interval,  or  266  persons  per  minute,  or  say,  10  persons  per  foot 


THE   HUDSON   TERMINAL   STATION  173 

of  width  of  stairs.  No.  3  platform  has  six  stairs  (one  not  fitted 
until  needed)  aggregating  48  \  feet  in  width  for  discharge  of 
800  persons  in  90  seconds,  or  say  9  persons  per  foot  of  width 
per  minute. 

For  the  loading  platforms,  it  was  important  for  the  economical 
operation  of  the  railroad  to  group  the  landings  on  the  concourse 
floor,  and  consequently  it  was  necessary  to  provide  for  this 
service  only  four  stairs  per  platform  in  pairs.  These  have  an 
aggregate  width  of  32.}  feet,  and  a  maximum  passenger  movement 
of  16  persons  per  foot  of  width  per  minute,  on  the  assumption 
that  the  train  is  fully  loaded  at  the  terminal  station  and  no  con- 
sideration given  to  local  movement  at  other  stations. 

The  arrangement  of  stairway  heads  on  the  concourse  floor 
tends  as  far  as  it  is  possible  to  thoroughly  distribute  the  move- 
ment, and  also  to  separate  the  incoming  from  the  outgoing 
traffic.  The  distribution  of  the  streams  of  traffic  cannot  be  too 
thoroughly  separated  to  obtain  the  best  results.  At  the  same 
time,  having  in  mind  that  when  the  movement  eastward  is  at 
its  maximum  and  carrying  7.5  per  cent  of  the  total  daily  traffic 
between  7  a.m.  and  8  a.m.,  the  westward  movement  is  only 
1.5  per  cent  of  the  total  daily  trafi&c;  and  in  reverse  direction 
when  between  5  p.m.  and  6  p.m.  the  maximum  westbound 
traffic  represents  10.7  per  cent  of  the  total  daily  traffic,  the 
eastbound  traffic  only  represents  2.5  per  cent  of  the  total  daily 
movement. 

The  original  plan  designed  was  to  absolutely  separate  the 
movement  on  the  street  by  making  two  main  entrances  on  Dey 
Street  near  Church  Street,  each  30  feet  wide,  the  entire  entrance 
for  all  the  traffic  descending  by  arcade  passages  and  easy  stairs 
to  the  concourse;  and  one  main  exit  each  at  Cortlandt  Street 
and  at  Fulton  Street,  each  30  feet  in  width,  and  ascending  by 
arcades  and  easy  ramp  sloping  from  10  to  14  per  cent  from  the 
concourse.  As,  however,  the  aggregate  of  these  main  entrances 
provided  for  less  than  9  persons  per  foot  of  width  per  minute 
and  the  office  buildings  were  greatly  benefitted  by  making  all 
these  main  approaches  equally  entrances  and  exits,  the  first 
plan  was  modified  to  that  extent  and  the  freedom  of  movement 


174      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

is  much  better  adapted  to  the  general  approach  through  the 
streets  to  the  station  and  reduces  thereby  the  general  congestion 
on  the  streets. 

The  first  essential  purpose  of  this  railroad  and  station  is 
for  the  operation  of  a  purely  local  rapid  transit  passenger  ser- 
vice, but,  as  before  stated,  the  railroad  was  also  to  operate  a 
terminal  service  for  the  various  steam  railroads  in  Jersey  City 
and  Hoboken.  It  was,  therefore,  also  necessary  to  equip  the  con- 
course floor  with  ticket  offices  for  these  various  trunk  line  rail- 
roads, enabling  them  to  sell  all  classes  of  tickets  for  all  points 
on  their  systems  for  trains  departing,  and  to  advertise  schedules 
of  trains  departing,  from  Church  Street  terminal.  A  train 
leaving  at  an  advertised  time  becomes  the  train  connection 
for  the  specified  steam  railroad  train  from  New  Jersey.  The 
ticket  examiners  at  the  ticket  barriers  on  the  concourse  floor 
announce  the  train  connection  and  at  the  leaving  time  of  the 
train  deliver  a  clearance  ticket  for  the  train  to  the  conductor, 
who  in  turn  surrenders  the  clearance  ticket  to  the  platform 
man  at  the  respective  stations  on  the  New  Jersey  side,  on 
receipt  of  which  ticket  the  main  line  train  is  despatched. 

The  construction  and  design  of  this  combined  station  and 
office  building  need  a  very  brief  description.  The  structure 
below  the  surface  is  the  greatest  example  of  caisson  construc- 
tion in  existence.  The  soil  underlying  the  site  was  quicksand 
down  to  the  level  of  the  hardpan,  which  was  an  irregulai  deposit 
overling  the  bedrock  (New  York  micaceous  gneiss).  All  sur- 
rounding buildings  were  on  old  and  inadequate  foundations, 
and  the  plans  for  the  electrical  power  plant  to  be  put  in  below 
the  track  level  required  excavation  to  a  depth  of  75.8  feet  below 
Church  Street,  or  50.7  feet  below  tide  level.  In  addition  to  the 
building  with  its  foundations,  the  approaches  for  the  tunnels 
to  the  station  at  either  end  had  also  to  be  constructed  by  sinking 
caissons  under  the  streets  and  from  building  line  to  building 
line  without  interfering  with  the  use  of  the  streets  during  con- 
struction. The  main  station  site  was  first  enclosed  by  sinking 
51  rectangular  caissons,  joined  to  each  other,  around  the 
external  lines.     All  these  caissons  are  of  reinforced  concrete,  8 


THK   IirDSON  TERMINAL  STATION  175 

feet  thickness  of  wall,  and  all  caissons  were  sunk  through  hard- 
pan  to  bedrock  and  sealed  into  the  rock.  Rock  at  its  deepest 
point  is  I  lo  feet  below  the  surface  of  Church  Street.  Inside 
the  area  of  the  enclosed  coffer-dam  were  then  sunk  1 1 5  circular 
pits  and  ^2  rectangular  pits,  in  caissons  down  to  hardpan,  these 
pits  corresponding  to  each  column  location;  and  in  these  pits 
were  constructed  the  grillages  and  foundations  for  columns. 
Up  to  this  point  excavation  had  only  been  carried  down  to  about 
the  concourse  floor  level  where  water  stood  in  the  ground.  The 
steel  columns  for  the  triple  tier  from  foundation  to  street  floor 
level  were  then  erected  in  these  pits;  the  lower  length  of  column 
weighing  as  much  as  26  tons  each  and  carrying  loading  up  to 
1725  tons  per  column.  The  columns  being  erected,  the  steel 
of  the  concourse  floor  was  then  erected  and  the  floor  filled  with 
solid  Portland  cement  concrete  from  wall  to  wall.  Excavation 
was  then  carried  down  to  the  train  deck.  From  that  floor  the 
main  girders  on  rectangular  system  between  columns  were  48 
inches  deep,  flanges  16  inches  wide.  The  floor  had  to  carry  the 
train  loading  as  well  as  to  be  the  main  strut  to  carry  the  external 
pressures  on  the  external  walls.  It  was,  therefore,  determined 
to  construct  this  of  excessive  mass  and  strength  by  putting 
in  a  solid  slab,  36  inches  thick,  of  reinforced  Portland  cement 
concrete,  burying  columns  and  girders  in  one  continuous  mass. 
The  enormous  external  pressure  may  be  appreciated  from  the 
fact  that  during  excavation  from  the  concourse  to  the  train 
floor  and  while  waiting  for  steel  girders  to  be  delivered,  the 
entire  wall  along  Church  Street  bowed  in  10  inches  without 
crack  or  apparent  injury. 

After  the  track  floor  construction  was  complete,  excava- 
tion was  carried  down  to  the  bottom.  The  bottom  of  the  rail- 
road's transformer  sub-station  Xo.  3  was  excavated  down 
to  bedrock.  The  entire  balance  of  area  of  basement  had  all 
quicksand  removed  to  hardpan  or  rock  and  the  area  backfilled 
with  boiler  cinders  and  thoroughly  sub-drained  to  the  sump 
where  automatic  ejectors  are  installed.  Since  construction, 
it  is  found  that  the  entire  drainage  through  the  walls  and  into 
the  foundations  is  insignificant  and  negligible.     To  construct 


176      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

this  basement  it  was  necessary  to  build  the  coffer-dam  continuous 
but  at  the  same  time  the  approaches  under  Cortlandt  Street 
and  Fulton  Street  were  also  being  sunk  in  caissons  connected 
end  to  end  with  removable  steel  end  walls  used  only  for  sink- 
ing purposes;  and  these  approaches  involved  T)2>  caissons  having  a 
total  cubic  capacity  of  25,000  cubic  yards.  These  being  sunk 
to  final  grade,  sealed,  roofed,  and  in  every  way  made  secure, 
the  trainways  through  the  main  coffer-dam  walls  were  blasted 
out.  This  was  a  most  difficult  job,  executed  while  the  office 
buildings  were  fully  occupied.  The  trainways  represented  120 
feet  of  regular  railroad  tunnel.  The  total  quantities  involved 
in  work  below  the  street  level,  as  illustrating  the  magnitude  of 
the  undertaking,  were  as  follows: 

..  238,000  cubic  yards  excavation 
80,000  cubic  yards  excavation  in  caissons 
11,000  cubic  yards  concrete  in  caissons 
6,267  tons  structural  steel 

In  the  basement  of  the  buildings  is  the  following  equipment : 

Electric  transformer  sub-station  transforming  current  gen- 
erated in  Jersey  City  power  house,  transmitted  at  11,000  volts 
a.c.  to  current  at  625  volts  d.c.  for  railroad  operation  and  240 
volts  d.c.  for  the  power  and  lighting  of  the  buildings. 

A  complete  school  of  instruction  for  railroad  employees, 
fitted  with  a  full-sized  car'and  signal  equipment. 

Club,  reading  and  dressing  rooms  for  employees. 

Suction  and  forced  draft  fans  for  tunnel  ventilation,  and 
also  similar  machinery  for  ventilation  of  the  basement  and 
the  buildings. 

Absorption  ice-making  plant  (Carbondale  type)  for  clubs, 
restaurants  and  markets. 

1500  h.p.  boiler  plant  (Babcock  &  Wilcox). 

Isolated   generating   plant    for    supplying   entire   buildings. 

Storage  battery  plant. 

Hydraulic  pumps  for  all  baggage  elevators. 

Extensive  baggage  rooms  and  space  for  handling  arwi  storage 
of  baggage  or  freight. 


THE   HUDSON   TERMINAL  STATION  Ut 

Coal  bunkers,  capacity  1500  tons,  constructed  of  reinforced 
concrete. 

In  addition  to  the  local  passenger  business  of  the  Hudson- 
Manhattan  Railroad,  it  is  obvious  from  the  foregoing  descrip- 
tions that  the  railroad  is  also  laid  out  to  be  the  distributing 
terminal  for  the  steam  trunk  lines  terminating  in  New  Jersey. 
This  is  anticipated  in  the  fact  that  the  company  is  now  con- 
structing a  physical  connection  to  the  tracks  of  the  Pennsylvania 
Railroad  so  that  its  electric  trains  can  be  run  over  the  tracks 
of  the  Pennsylvania  Railroad  from  the  suburban  district  in 
New  Jersey  into  the  tunnels  of  the  Hudson  and  Manhattan 
Railroad,  either  to  the  Church  Street  terminal  or  ultimately 
uptown  to  Forty-second  Street,  Grand  Central  Station.  Further 
than  this,  a  connection  is  anticipated  from  the  Eric  direct  to 
the  Church  Street  terminal. 

For  handling  baggage  there  are  four  elevators  of  the  Otis' 
plunger  type,  the  floor  area  of  each  averaging  12  by  6  feet. 
These  elevators  are  equipped  with  rams  gi  to  122  inches  in 
diameter  and  have  a  lift  of  23  feet;  capacity  of  the  elevators 
is  8000  to  13,000  pounds.  One  of  these  elevators  is  installed 
at  each  end  of  each  of  the  loading  platforms,  and  the  main  Dey 
Street  baggage  elevators  serve  the  No.  6  platform  by  a  door 
opening  onto  that  platform  direct.  The  means  is,  therefore, 
provided  for  getting  baggage  onto  each  or  any  one  of  the  plat- 
forms serving  the  live  separate  tracks  at  either  end. 

The  development  and  use  for  railroad  purposes  of  the  space 
below  street  level  only,  allowed  of  the  full  treatment  above  the 
surface  of  almost  the  entire  area.  This  very  great  area  per- 
mitted the  design  of  oflEice  buildings  on  strictly  economical 
lines  which  would  be  noteworthy  and  handsome  if  for  no  other 
reason  than  on  account  of  their  enormous  mass  and  simplicity. 

There  are  two  of  these  buildings  22  stories  in  height  above 
the  street,  the  combined  cubical  contents  of  which  are  approxi- 
mately 15,000,000  cubic  feet.  Both  of  these  superstructures 
were  so  designed  as  to  have  easy  access  from  the  elevator  halls 
to  the  concourse  floor  below. 

The    Sixth   Avenue   elevated    station   at    Cortlandt    Street 


178      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

connects  with  the  corridors  on  the  third  floor  of  the  building 
on  Cortlandt  Street  and  the  twin  buildings  are  connected  by  a 
bridge  on  this  floor  crossing  Dey  Street. 

There  are  39  high-speed  i-to-i  traction  elevators,  22  of  vv'hich 
are  express  elevators  running  to  the  twenty-second  floor,  and  17 
local  elevators  running  to  the  eleventh  floor.  Three  of  the  ele- 
vators run  down  to  the  concourse  floor,  but  are  not  at  present 
used  except  in  cases  of  emergency. 

The  rental  area  of  the  buildings  is  approximately  815,000 
square  feet,  exclusive  of  the  valuable  rental  space  on  the  entire 
concourse  floor. 

In  order  to  construct  these  buildings  enormous  quantities 
of  materials  were  required;  there  are  approximately  17,000,000 
bricks  above  the  surface  of  the  ground,  and  in  the  sub- 
structure and  super-structure  combined  there  are  27,000  tons 
of  steel. 

There  are  four  entrances  to  the  railroad  station,  or  concourse 
floor.  The  approaches  on  Cortlandt  and  Fulton  Streets  are 
by  means  of  ramps  and  the  two  on  Dey  Street  by  means  of 
stairways.  These  approaches  are  very  simple  in  design  and 
are  arranged  with  shop  windows  all  around.  At  the  ends  of 
these  approaches  are  four  large  clock  panels  designed  by  Mr. 
Carl  Bitter.  Steel  and  glass  marquises  cover  the  entire  width 
of  the  sidewalk  over  all  entrances.  The  floors  of  the  ramps 
are  of  cement  mixed  with  carborundum  so  as  to  avoid  slipping. 
The  stairways  are  of  bluestone. 

All  renting  spaces  are  designed  on  a  strictly  commercial 
basis  and  the  entire  station,  including  the  concourse  floor  and 
the  railroad  platforms,  are  built  so  as  to  be  as  sanitary  as  pos- 
sible. The  floor  of  the  concourse  is  of  white  terrazza  with  colored 
mosaic  bands,  and  all  walls  and  columns  have  a  white  glazed 
terra  cotta  wainscoting  with  sanitary  base  and  decorative  cap 
of  the  same  material.  The  walls  above  the  wainscoting  are 
of  hard  plaster;  all  angles  are  coved  or  round,  and  the  entire 
plaster  work  is  painted  with  enamel  paint. 

On  the  concourse  floor  every  convenience  of  the  modern 
terminal  station  is  provided  for  the  public  and  every  effort  has 


THE  HUDSON  TERMINAL  STATION  179 

been  made  to  make  it  attractive.  This  floor  is  approximately 
430  feet  long  by  185  feet  wide,  and  of  this  space  aisles  which 
approximate  a  total  of  100  feet  in  width  arc  given  up  to  the 
public,  with  ticket  booths  arranged  at  convenient  points,  giving 
an  unobstructed  view  of  the  whole  length  of  the  floor.  On  this 
floor,  in  addition  to  the  ticket  ofiices  of  the  Hudson  and  ]\Ian- 
hattan  Railroad  Company,  are  the  ticket  offices  of  the  Penn- 
sylvania, Erie  and  Lehigh  Valley  Railroads.  There  are  ample 
waiting  rooms  with  first-class  toilet  accommodations;  and  bag- 
gage and  parcel  rooms,  barber  shops,  bootblacks,  telephone 
and  telegraph  booths,  and  shops  at  which  nearly  everything 
that  the  commuter  requires  may  be   purchased. 

This  combination  of  a  railroad  terminal  and  an  ofiice  build- 
ing above,  presented  problems  which  would  not  arise  in  the 
case  of  either  proposition  if  handled  by  itself.  The  most  serious 
of  these  is  the  arrangement  of  the  columns  so  that  as  far  as 
possible  they  would  allow  of  a  proper  architectural  treatment 
of  the  buildings  and  still  maintain  the  right-of-way  of  the  tracks 
in  the  sub-structure.  This  was  accomplished  in  the  main 
body  of  the  plot,  but  at  the  Cortlandt  and  Fulton  Street  ends 
where  the  tracks  converge  to  run  down  the  streets,  it  was  found 
necessary  to  have  the  building  columns  rest  on  girders,  which 
were  carried  by  columns  extending  through  the  track  floor, 
which  columns  were  located  so  as  to  leave  proper  clearance 
for  the  tracks.  The  distributing  girders  were  placed  at  the 
concourse  floor  level  and  are  made  up  of  three  single  girders, 
each  72  inches  deep,  with  a  flange  width  of  10  inches;  and  as 
these  girders  when  set  up  were  very  wide,  and  it  being  almost 
impossible  to  design  proper  caps  for  the  columns  which  supported 
them,  mill  slabs  of  steel  were  used;  these  were  in  some  cases 
6  inches  thick. 

Another  point  which  had  to  be  taken  care  of  was  the  multitude 
of  pipes  and  wires  which  were  necessary  to  connect  the  build- 
ings above  the  track  and  concourse  floors  with  the  power  and 
heating  plants  which  were  located  below  these  floors,  partic- 
ularly bearing  in  mind  that  the  passage  through  the  track  floor 
must  not  by  any  connections  obstruct  more  than  necessary  the 


180  SUBWAYS  AND  TUNNELS   OF  NEW  YORK 

space  occupied  by  platforms.  This  was  accomplished  by  con- 
necting up  groups  of  pipes  or  wires  into  systems  of  piping 
which  for  convenience  were  termed  sub-mains,  which  sub-mains 
were  in  turn  connected  to  the  mains  in  the  basement  by  means 
of  large  vertical  risers  termed  sub-main  feeders.  By  this  means 
the  amount  of  room  required  for  piping  and  wire  shafts  was 
reduced  to  a  minimum;  and  as  these  are  usually  placed  near 
columns,  the  size  of  the  finish  around  columns  was  reduced 
quite  materially  and  thereby  unnecessary  obtruction  of  the 
track  platforms  was  avoided. 

These  sub-mains  were  placed  near  the  concourse  ceihng 
and  to  make  proper  finish  for  the  concourse  a  hung  ceiling  was 
erected  under  same  with  trap  doors  for  easy  access  to  the  con- 
trol valves. 

The  entire  lighting  of  the  buildings  and  sub-structure  is 
by  means  of  high  efficiency  lamps  and  specially  designed 
fixtures-. 

The  location  of  these  twin  buildings  in  conjunction  with 
the  railroad  station  terminal  has  created  a  new  center  of  popula- 
tion where  previously  only  a  small  community  was  gathered. 
The  present  aggregation  of  persons  transacting  their  daily 
work  under  these  roofs  is  8000  and  with  the  complete  rental 
of  all  space  will  amount  to  approximately  10,000. 

The  property  was  purchased  in  the  early  part  of  1906  and 
some  few  buildings  standing  thereon  were  razed  at  that  time. 
It  was  not,  however,  until  May  i,  1906,  that  the  bulk  of  the 
properties  was  turned  over  to  the  railroad  company.  The 
company  by  its  own  engineers  carried  out  all  work  of  construc- 
tion of  the  railroad  station,  approaches,  foundations  and  sub- 
structure below  street  level.  The  caisson  and  foundation  work 
had  advanced  so  that  on  May  12,  1907,  the  first  grillage  and 
column  were  set  in  the  permanent  structure,  and  on  April  4, 
1908,  the  company  moved  into  its  offices  in  the  completed  build- 
ing. The  completion  of  tunnel  approaches,  tunnels  and  ter- 
minal station,  however,  took  considerably  longer,  the  railroad 
going  into  operation  July  19,  1909. 

The  design  and  construction  of  tunnels,  station  and  sub- 


THE   HUDSON   TERMINAL  STATION  181 

structure  were  by  Jacobs  &  Davies,  engineers  of  the  company, 
while  the  entire  design  of  the  buildings,  and  treatment  and 
decoration  of  the  station  were  bv  Clinton  &  Russel,  architects. 
George  A.  Fuller  Company  was  the  contractor  for  the  buildings. 

From  a  paper  before  American  Institute  of  Architects  by  J.  Vipond   Davies 
and  J.  Hallis  Wells. 


APPENDICES 


APPENDICES 

A.  Air  Compressors  in  the  New  York  Tunnel  Work. 

B.  The  Compressed  Air  Plenum. 

C.  The  Use  of  Compressed  Air  in  Tunneling. 

D.  Special  Types  of  Air  Compressors. 

E.  Straight  Line  and  Duplex  Compound  Air  Compressors. 

F.  Compound  Air   Compression;    Altitude  Compression;   Air 

Cylinder  Lubrication. 

G.  Some  Air  Lift  Data. 

H.    Compressed  Air  Locomotives. 

I.      Rock  Drills;  Hammer  Drills. 

J.   ^  Tunnel  Carriage  for  Drilling;  Electric- Air  Drill. 

K.    Rock  Drill  Bits;  Drill  Sharpening. 

L.     Selection  of  Explosives;  Dampness  and  Dynamite;  Blasting 

Gelatine;  Cost  of  Blasting  in  Open  Cuts. 
M.    Pumps  for  Sinking  and  Tunneling;  Sinking  Caissons. 
N.    Engineering  Data. 


184 


APPENDIX   A 

Air  Compressors  on  New  York  Tunnel  Work 

The  tunnel  stage  of  the  development  of  New  York  City 
may  be  said  to  have  really  commenced  with  the  present  century. 
Although  the  first  tunnel  under  the  North  River  was  planned 
and  begun  a  quarter  of  a  century  ago,  it  has  but  recently  been 
completed,  with  also  its  twin  tunnel  for  the  reciprocal  traffic. 
On  account  of  the  earher  completion  of  connections,  other 
tunnels  begun  within  the  present  century  will  be  in  established 
service  before  these. 

The  tunnels  completed  or  approaching  completion,  includ- 
ing the  two  mentioned  above,  are  as  follows: 

Six  tunnels  under  the  North  River;  the  two  from  Morton 
Street,  Manhattan,  to  Hoboken  to  be  used  for  local  and  sub- 
urban electric  train  service;  two  near  Cortlandt  Street  for  the 
same  system;  two  at  about  Thirty- third  Street  for  the  Penn- 
sylvania Railroad.  Eight  under  the  East  River;  two  from  the 
Battery  up  into  the  heart  of  Brooklyn,  as  a  continuation  of  the 
already  completed  subway;  four  to  connect  the  Pennsylvania 
Railroad  with  the  Long  Island  Railroad,  two  of  these  tunnels 
also  extending  across  ^Manhattan;  and  the  two  so-called  Bel- 
mont tunnels  which  are  to  connect  the  Forty-second  Street  line 
of  the  present  subway  with  Long  Island  trolley  lines. 

This  tunnel  work  involves  not  only  the  actual  driving  of 
the  tunnels  under  the  rivers  as  indicated,  but  greater  additional 
lengths  of  subterranean  tunneling  for  the  approaches  or  con- 
nections. Other  tunnels  "  too  numerous  to  mention  "  in  these 
and  other  directions  are  planned  and  more  or  less  specifically 
provided  for  to  supply  work  for  at  least  twenty  years  ahead, 
by  which  time  the  tunnel  habit  will  have  become  so  estabHshed 

185 


186  SUBWAYS   AND  TUXNELS   OF  NEW  YORK 

that  no  one  now  can  suggest  the  amount  of  subterranean  and 
subaqueous  excavation  and  construction  which  will  ultimately 
be  required  in  New  York  and  vicinity. 

We  have  here  to  do  with  only  one,  although  the  most  import- 
ant, physical  agency  in  all  this  tunnel  work,  the  compressed 
air  supply.  Merely  to  enumerate  the  air  compressing  plants 
which  have  been  installed  in  New  York  for  tunnel  work  alone, 
with  mention  of  a  few  of  their  most  important  details,  is  enough 
for  the  present  paper. 

It  will  be  noted  that  all  the  air  compressors  herein  enu- 
merated are  New  York  machines,  machines  largely  developed 
by  New  York  practice  in  the  building  of  the  Aqueduct,  supple- 
mented by  mine  and  tunnel  work  throughout  the  world;  and 
perfected  and  manufactured  by  the  two  New  York  companies 
of  world-wide  reputation  in  this  line,  the  Ingersoll-Sergeant 
and  the  Rand,  now  in  the  natural  course  of  business  events 
combined  in  a  single  concern,  the  Ingersoll-Rand  Company. 
The  position  of  this  company  in  this  great  metropohtan  develop- 
ment is  unique,  and  cannot  be  approached  for  parallel  or  com- 
parison in  any  other  line  of  business. 

That  there  is  plenty  of  tunnel  work  ahead  for  the  air  com- 
pressor might  well  be  inferred  from  the  substantial  and  appar- 
ently permanent  character  of  many  of  the  installations.  Sev- 
eral of  the  plants  here  mentioned  will  undoubtedly  be  employed 
to  supply  the  air  for  other  tunnels  besides  those  for  which  they 
have  been  originally  erected.  These  plants  accordingly  have 
generally  nothing  cheap  or  temporary  about  them.  They 
employ  all  the  usual  well-known  devices  of  economy  both  in 
the  use  of  steam  and  in  the  compression  of  the  air.  The  boilers 
are  all  of  modern  design  and  nearly  all  of  the  water-tube  type. 
The  steam  units  are  usually  compound  and  condensing,  and  the 
air  compression  two  stage  with  intercoolers  and  aftercoolers. 
Gravity  oiling  systems  are  installed,  which  constantly  and 
perfectly  lubricate  every  part  and  return  the  oil  for  repeated 
use.  The  action  of  the  compressors  is  regulated  automatically 
according  to  the  call  for  the  air.  so  that  a  series  of  machines  will 
run  constantly  without  handling  the  throttle.     Recording  gages 


APPENDIX   A  187 

arc  generally  employed  and  their  records  are  watched  and  filed 
in  the  offices. 

While  as  a  rule  nothing  has  been  neglected  in  the  installa- 
tion of  these  plants  which  could  contribute  to  the  reliability 
and  economy  of  their  operation,  to  the  accessibility  of  i)arts 
and  to  convenience  of  manipulation,  so  that,  seen  within  and 
with  all  the  circumstances  considered,  many  of  them  may  be 
taken  as  models  of  their  class,  but  the  slightest  thought  has 
been  given  to  the  exteriors  of  the  buildings.  One  plant  is  located 
in  an  old  church,  another  in  a  dilapidated  foundry,  and  in 
several  cases  the  compressors,  boilers,  etc.,  have  been  com- 
pletely placed  in  the  open  air  and  their  protective  sheds  or 
buildings  have  been  erected  over  them. 

The  perfection  and  endurance  of  the  compressors  may  be 
noted  as  remarkable.  The  writer  hereof  more  than  a  year  ago 
personally  visited  every  plant  mentioned  except  that  upon 
]Man-0'-War's  Reef,  the  improvised  island  in  the  East  River; 
and  while  most  of  the  compressors  seen  were  being  worked  to 
the  limits  of  their  capacity,  running  at  speeds  which  were  aston- 
ishing, not  one  was  seen  out  of  order  or  undergoing  repairs. 
The  arduous  work  on  the  New  York  Aqueduct  and  in  tunnels 
and  mines  everywhere  has  to  a  remarkable  extent  revealed  and 
eliminated  the  weak  spots  and  suggested  successive  improve- 
ments. 

As  indicating  the  speeds  at  which  these  compressors  may 
be  run,  it  may  be  specially  noted  that  five  duplex  Corliss  com- 
pressors, 42-inch  stroke,  in  the  Manhattan  plant  of  S.  Pearson 
&  Son,  Inc.,  were  designed  and  guaranteed  to  run  continuously 
at  100  r.p.m.,  or  700  feet  piston  speed,  with  a  further  provision 
that  in  case  of  emergency  they  would  be  capable  of  running  at 
125  r.p.m.  for  a  period  not  exceeding  twenty-four  hours.  This 
emergency  has  been  encountered  several  times  since  the  plant 
was  installed,  and  in  fact  the  machines  have  run  as  high  as  135 
r.p.m.  or  945  feet  piston  speed,  for  long  periods  without  appar- 
ent distress. 

In  the  estimated  free  air  capacities  given  herein  for  each 
plant  the  piston  speed  assumed  for  all  is  500  feet  per  minute. 


188      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

The  one-quarter  inch  additional  to  the  nominal  diameters  of 
the  IngersoU  air  cylinders  is  dropped  out  of  the  computations, 
as  this  normally  compensates  for  the  area  of  the  piston  inlet 
pipe,  although  in  some  of  the  compressors  with  mechanically 
operated  valves  this  pipe  is  not  used. 

Pennsylvania  Station  Excavation.  The  work  of  excavating 
for  the  New  York  terminal  of  the  Pennsylvania  Railroad  is 
not  at  all  tunnel  work,  but  it  is  at  the  point  where  four  of  the 
tunnels  are  to  meet.  This  work  was,  to  think  of,  a  simple  affair. 
It  was  only  to  dig  a  hole  in  the  ground;  but  it  was  a  hole 
measuring  roughly,  in  the  main  portion  of  it,  1800  by  400  feet 
and  40  feet  deep,  with  more  than  1,500,000  cubic  yards  of 
material  to  be  removed.  A  considerable  portion  of  the  top  was 
sand  and  gravel,  which  was  removed  first,  but  most  of  the 
material  is  solid  rock.  Both  steam  and  compressed  air  are 
employed  on  the  work.  The  steam  shovels,  being  self-contained, 
also  some  traveling  derricks  and  of  course  all  the  locomotives, 
are  steam  operated;  while  rock  drills,  pumps,  many  hoists, 
concrete  mixers,  etc.,  are  driven  by  compressed  air;  and 
here,  as  elsewhere,  the  compressors  are  driven  to  their  full 
capacity. 

A  temporary  compressor  plant  was  first  installed  right 
upon  a  portion  of  the  ground  to  be  excavated,  the  exterior  of 
the  plant  being  shown  in  Fig.  i .  The  church  and  appurtenances 
in  the  background  have  since  been  pulled  down  and  rock  cutting 
is  proceeding  upon  the  site.  There  were  here  three  Rand 
straight  line  Class  "  C  "  compressors  with  cylinders  24-  and 
26-inch  diameter  by  30-inch  stroke,  free  air  capacity  5529 
cubic  feet  per  minute;  and  one  IngersoU  Class  "A"  piston 
inlet  compressor  24-  and  26^-  by  30-inch  stroke,  free  air  capacity 
1843  cubic  feet  per  minute.  The  steam  cyhnders  had  balanced 
valves  and  Meyer  adjustable  cut-offs  and  worked  non-con- 
densing. The  steam  pressure  carried  was  no  pounds  and  the 
air  pressure  90  pounds,  the  latter  not  being  always  maintained, 
as  the  air  was  used  as  fast  as  it  could  be  delivered.  The  rock 
drilling,  however,  was  kept  constantly  in  advance  of  the  work 
of  removal  and  many  holes  were  always  waiting  to  be  fired 


APPENDIX  A 


189 


when  needed.  The  air  was  not  cooled  except  by  the  water 
jacket.  There  were  two  large  air  receivers  and  a  combined 
delivery  pipe  8  inches  in  diameter  with  valves  for  disconnecting 
each  compressor.  The  air  line  was  carried  around  the  excava- 
tion with  distributing  branches  where  required.  There  were 
six  locomotive  boilers  burning  small  anthracite.  A  Cochrane 
feed  water  heater  was  in  service  and  two  duplex  steam  pumps 
for  boiler  feeding. 

It  was  well  to  mention  this  plant  first,  since  it  was,  with 
perhaps  one  exception,  the  least  economical  of  any  of  the  plants 


Fig.  1. — Temporary  Power  House,  Pennsylvania  Terminal. 


here  enumerated.  Fig.  2  shows  the  exterior  and  PMg.  3  the 
interior  of  the  more  permanent  installation  of  the  New  York 
Contracting  Company  for  this  Pennsylvania  terminal  excava- 
tion. This  is  a  plant  of  much  larger  capacity  and  does  its 
work  much  cheaper.  The  building,  as  is  evident,  was  a  church, 
but  the  interior  is  now  as  unecclesiastical  as  could  well  be 
imagined. 

There  are  here  three  2-stage,  electrically  driven  Rand 
compressors  with  air  cylinders  30-  and  19-inch  diameter  by  30- 
inch  stroke;  free  air  capacity  8983  cubic  feet  per  minute.  The 
induction  motors  are  each  500  h.p.  General  Electric,  type  L.M., 


190 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


122  r.p.m.,  6600  volts,  3-phase,  25-cycle.  There  is  also  one 
Rand  Corliss,  cross-compound,  girder  frame,  2-stage  compressor 
with  steam  cyUnders  22-  and  40-inch  and  air  cyhnders  38-  and 
23-inch  by  48-inch  stroke;  free  air  capacity  3937  cubic  feet 
per  minute.     In  addition  to  these  are  the  four  compressors  of 


A  A 


.:^^ 


Fig.  2. — Exterior  of  Power  House,  Pennsylvania  Terminal  Excavation 

the  temporary  plant  previously  enumerated  and  therefore 
not  mentioned  further  and  not  repeated  in  our  final  sum- 
mary of  the  various  plants. 

Pennsylvania  Railroad  East  River  Tunnels,  Manhattan  Plant. 
The  plant  of  the  contractors,  S.  Pearson  &  Son,  Inc.,  at  Thirty- 
third  Street  and  First  Avenue,  New  York,  is  in  marked  contrast 


APPENDIX   A 


191 


to  the  preceding.  Fig.  4  is  a  snap-shot  of  the  exterior  and  Fig. 
5  shows  the  interior.  The  entire  equipment  in  this  case  was 
installed  under  the  direction  of  the  builders  of  the  compressors, 
the  Ingersoll-Rand  Company.  There  are  four  cross-compound 
Corliss  compressors  with  steam  cylinders  16-  and  34-  by  42-inch 
stroke,  and  duplex  air  cylinders  26', -inch,  for  a  maximum  air 
pressure  of  50  jxmnds;  free  air  capacity,  14.744  cubic  feet  per 
minute.     There  is  another  cross-compound  Corliss  compressor 


Fig.  3. — Interior  of  Power  House  for  P.R.R.  Terminal  Excavation. 


of  the  same  stroke  and  with  the  same  steam  cylinder  dimensions 
as  the  above,  but  with  duplex  air  cylinders  155-inch  diameter 
designed  to  compress  to  140  pounds  air  pressure.  The  air  for 
this  compressor  may  be  taken  into  the  cylinders  at  the  atmos- 
pheric pressure,  or  it  may  be  taken  in  at  40  or  50  pounds  pres- 
sure from  the  aftercooler  of  the  low  pressure  service,  thus  increas- 
ing its  delivery  at  the  high  pressure  about  fourfold;  free  air 
capacity,  13 10  cubic  feet  per  minute.  Another  compressor 
has  a   special   combination   feature.     It   is   a   cross-compound 


192 


SUBWAYS  AND  TUNNELS   OF  NEW  YORK 


Corliss  compressor  with  the  same  steam  cylinder  dimensions 
as  above,  but  with  tandem  air  cylinders  23^  and  15I  inches  in 
diameter  on  each  side.  All  the  air  cylinders  may  be  used  to 
compress  atmospheric  air  to  50  pounds  pressure  and  deHver 
individually  into  the  low  pressure  service;  or,  by  disconnect- 
ing the  23|-inch  cylinders,  the  smaller  cylinders  may  be  used 
for  the  high  pressure  service,  140  pounds,  precisely  the  same 
as  the  preceding  machine.  Free  air  capacity  of  this  com- 
pressor is  4194  cubic  feet  per  minute.  Besides  these,  there 
are  two    straight  Hne   Class   "A"   compressors  18-  and   i8|- 


FiG.  4. — Manhattan  Power  House  for  P.R.R.  East  River  Tunnels. 


by  24-inch  stroke  used  for  preliminary  development  work 
and  generally  held  in  reserve;  free  air  capacity,  1766  cubic 
feet  per  minute.  This  is  the  plant  mentioned  above,  guaran- 
teed to  w^ork  up  to  a  piston  speed  of  700  and  in  emergencies 
to  875  feet  per  minute,  and  which  has  been  run  up  to  945 
feet  in  actual  work. 

There  are  here  six  500  h.p.  Sterling  boilers,  three  Wheeler 
condensers,  with  independent  Edwards  air  pumps,  three  cen- 
trifugal pumps  of  the  Buffalo  Forge  Company  supplying  water 
from  the  East  River  for  jackets,  intercoolers,  aftercoolers  and 
condensers,  duplex  boiler  feed  pumps  in  duplicate,  a  separate 


APPENDIX  A 


193 


194 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


system  of  gravity  lubrication,  a  special  loop  steam  system 
with  Holly  drip  arrangement,  and  a  chemical  oil  separator.  A 
working  steam  pressure  of  150  pounds  is  carried  throughout 
and  everything  possible  is  run  condensing  except  what  is  required 
for  heating  the  feed  water.  The  power  house  contains  three 
high  speed  engines  with  direct-connected  generators  and  three 
duplex  high  pressure  hydraulic  pumps  automatically  controlled 
to  supply  water  for  advancing  the  shields,  with  which  we  here 
have  nothing  to  do.  Total  free  air  capacity  of  plant  is  22,014 
cubic  feet  per  minute. 


Fig.  6. — Long  Island  City  Power  House  for  P.R.R.  East  River  Tunnels. 


Pennsylvania  Railroad  East  River  Tunnels,  Long  Island  City 
Plant.  This  plant  of  S.  Pearson  &  Son,  Inc.,  at  Flushing 
Street  and  East  River  has  the  same  units  as  the  above,  except 
that  it  has  no  Class  "A"  compressors,  and  the  entire  plant  is 
quite  differently  arranged,  the  large  yard  space  allowing  great 
length  for  the  power  house.  Fig.  6  is  a  snap-shot  of  the 
exterior.  The  vertical  pipes  which  will  be  noticed,  capped  with 
strainers,  are  for  the  intake  air.  Instead  of  the  Class  "  A  " 
compressors  an  additional  Corliss  compressor,  the  same  as  the 
others   for  low  pressure  air,  was   installed,   making    the    total 


APPENDIX  A 


195 


free  air  capacity  of  the  plant  at  500  feet  piston  speed  23,934 
cubic  feet  per  minute. 

Pennsylvania  Railroad  North  River  Tunnels,  Manhattan 
Plant.  The  plant  of  the  O'Rourke  Engineering  Construction 
Company  at  Thirty-third  Street  and  Eleventh  Avenue,  New 
York  City,  the  general  exterior  of  which  is  shown  in  Fig. 
7,  comprises  three  Inger&oll-Rand  Corliss  compressors  with 
steam  cylinders  14-  and  30-  by  36-inch  stroke  and  duplex  air 
cylinders  23i-inch  diameter,  for  maximum  air  pressure  of  50 
pounds;  free  air  capacity,  8652  cubic  feet  per  minute.     There 


Fig.  7. — Manhattan  Power  House  for  P.R.R.  North  River  Tunnels. 


is  also  one  cross-compound  Corliss  compressor  with  steam 
cylinders  14-  and  22-  by  36-inch  stroke  and  duplex  air  cylinders 
i4i-inch  diameter  to  compress  to  140  pounds,  using  either 
free  air  or  air  taken  from  the  aftercoolers  of  the  low  pressure 
compressors.  Free  air  capacity  is  1068  cubic  feet  per  minute. 
Pennsylvania  Railroad  North  River  Tunnels,  Weehawken 
Plant.  This  plant,  also  of  the  O'Rourke  Engineering  Construc- 
tion Company,  foot  of  Baldwin  Avenue  and  North  River, 
Weehawken,  N.  J.,  is  an  exact  duplicate  of  the  preceding.  Total 
free  air  capacity  is  9720  cubic  feet  per  minute.  The  interior 
of  this  plant  is  seen  in  Fig.  8. 


196 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


Pennsylvania  Railroad  Tunnel  Under  Bergen  Hill.  This 
plant  of  the  John  Shield's  Construction  Company  at  Hemp- 
stead, N.  J.,  comprises  one  IngersoU  Class  "  A  "  compressor, 
24-  and  24^-  by  30-inch,  free  air  capacity  1570  cubic  feet  per 
minute;  and  four  Rand  Class  "  C  "  24-  and  24-  by  30-inch,  free 
air  capacity,  6280  cubic  feet  per  minute. 


Fig.  8. — Interior  of  Weehawken  Power  House  for  P.R.R. 
North  River  Tunnels. 


New  York  and  Brooklyn  Subway  Tunnel,  Battery  Park, 
Manhattan.  The  principal  compressor  in  this  plant  of  the 
New  York  Tunnel  Company,  the  contractors,  is  an  Ingersoll- 
Rand  cross-compound  Corhss,  steam  cylinders  24-  and  44-inch 
diameter  and  48-inch  stroke,  with  2-stage  piston  inlet  air 
cyhnders  36^-  and  22^-inch  diameter.  The  engine  has  its  own 
air  pump  and  condenser;  free  air  capacity,  3534  cubic  feet  per 
minute.  This  compressor  was  originally  installed  at  Jerome 
Park  Reservoir,  where    it  was   in    service    about    six    years. 


APPENDIX  A  197 

Besides  this,  there  are  two  IngersoU  Class  "A  "  compressors, 
24-  and  24^-  by  30-inch  stroke,  free  air  capacity  3140  cubic 
feet  per  minute.  There  are  two  Heine  and  two  Hogan  water 
tube  boilers. 

New  York  and  Brooklyn  Subway  Tunnel,  Joralemon  and 
Forman  Streets,  Brooklyn.  This  plant,  while  of  considerably 
larger  total  capacity  than  that  at  Battery  Park,  has  for  its 
largest  unit  the  other  Jerome  Park  Reservoir  compressor,  an 
IngersoU  cross-compound  Corliss  with  steam  cylinders  24-  and 
44-inch  diameter  by  48-inch  stroke  and  single  stage,  piston 
inlet  air  cylinders  24^-inch  diameter.  Free  air  capacity  is  3140 
cubic  feet  per  minute.  This  compressor  also  has  its  own  air 
pump  and  condenser.  There  are  also  two  IngersoU  cross-com- 
pound Class  "  GC  "  compressors  with  steam  cylinders  22-  and 
34-inch  diameter  by  24-inch  stroke  and  single  stage  piston 
inlet  air  cylinders  30^  and  28i-inch  diameter.  The  difference 
in  the  diameters  of  these  cylinders  is  due  to  the  exigencies  of 
manufacture  when  the  machines  were  required  at  very  short 
notice.  These  compressors  were  not  required  to  compress  the 
air  to  above  25  or  30  pounds;  free  air  capacity,  9184  cubic  feet 
per  minute. 

There  is  one  Rand  Class  "  B-4  "  cross-compound  compressor 
with  single  stage  air  cylinders,  steam  cylinders  20-  and  32-inch 
diameter  by  30-inch  stroke  and  air  cylinders  26-inch  diameter, 
free  air  capacity,  3686  cubic  feet  per  minute;  and  two  Inger- 
soU Class  "  A  "  straight  line  piston  inlet  compressors,  24-inch 
steam  and  24j-inch  air  by  30-inch  stroke,  free  air  capacity, 
3140  cubic  feet  per  minute. 

Belmont  East  River  Tunnel  Plants.  As  these  were  the  subject 
of  a  previous  article  (see  Chapter  XVIII)  we  here  merely  enume- 
rate the  sizes  and  capacities  of  the  compressors  employed.  At 
Forty-second  Street,  Manhattan,  there  is  in  one  power  house  a 
Rand  cross-compound  Corliss  2-stage  air  compressor  with  steam 
cylinders  24-  and  40-  by  48-inch  stroke  and  air  cylinders  39- 
and  24-inch;  free  air  capacity,  4147  cubic  feet  per  minute; 
and  an  IngersoU  cross-compound  Corliss  2-stage  compressor 
with   steam    cylinders   22-  and  40-  by  42-inch   stroke,  and  air 


198 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


cylinders  38-  and  24-inch;  free  air  capacity,  3937  cubic  feet 
per  minute.  In  the  other  power  house  there  are  three  Inger- 
soll  cross-compound  steam,  duplex  air  Class  "  H  "  compress- 
ors with  steam  cylinders  15-  and  28-  by  16-inch  stroke  and  air 
cyUnders  20j-inch  diameter,  for  a  maximum  pressure  of  50 
pounds;  free  air  capacity  6540  cubic  feet  per  minute.  There 
is  also  an  Ingersoll  cross-compound  steam,  2-stage  air,  Class 
"  HC  "  compressor  with  steam  cyUnders  and  stroke  as  above, 


Fig.  9. — Erecting  Compressors  in  Manhattan  Power  House 
for  the  Belmont  Tunnels. 


but  with  air  cylinders  25^-  and  16^-inch  diameter,  for  loc 
pounds  air  pressure;  free  air  capacity  1704  cubic  feet  per  min- 
ute. Fig.  9  shows  one  of  those  compressors  being  set  up  in 
place  before  the  house  was  built  over  it. 

On  ]\Ian-0'-\Var's  Reef  there  are  three  duplex  Class  "  J  " 
Ingersoll  belted  compressors  with  air  cylinders  20j-inch  diameter 
by  18-inch  stroke,  for  50  pounds  pressure;  aggregate  free  air 
capacity.  6540  cubic  feet  per  minute;  'one  electric  belted  2- 
stage  machine  for  100  pounds  pressure  with  air  cylinders  254- 
and  i6i-inch  diameter  by  18-inch  stroke;  free  air  capacity,  1704 
cubic  feet  per  minute;  and  two  Ingersoll  Class  "  A  "  straight 
Hne  compressors,    24-inch  diameter    steam,   26^-inch    diameter 


APPENDIX  A 


199 


air,  by  30-inch  stroke;    free  air  capacity,  3686  cubic  feet  per 
minute.     See  Fig.  10. 

At  the  Long  Island  City  plant  there  are  two  Ingersoll  cross- 
compound  steam,  2-stage  air  Class  "  H  "  compressors  with  steam 
cyhnders  15-  and  28-  by  16-inch  stroke,  and  air  cyHnders  25^ 
and  16^,  for  100  pounds  air  pressure;  free  air  capacity,  3408 
cubic  feet  per  minute.  There  are  here  also  two  Ingersoll  Class 
*'A"  compressors  24-  and  264-  by  30-inch  stroke,  free  air  capac- 


FiG.  10.— Power  House  tor  Belmont  Tunnels  on  Man-o'-War's  Reef. 


ity,  3686  cubic  feet  per  minute;  and  one  Class  '*  A  "  com- 
pressor 24-  and  24^-  by  30-inch  stroke,  free  air  capacity,  1570 
cubic  feet  per  minute.     See  Fig.  11. 

Hudson  Companies'  North  River  Tunnels,  Morton  Street, 
Manhattan.  This  pair  of  tunnels  now  completed  was  begun, 
or  one  of  them,  a  quarter  of  a  century  ago,  the  work  having 
been  stopped  by  serious  accidents  and  financial  difficulties. 
The  final  plant  here  comprised  one  duplex  Rand  compressor 


200 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


22- by  24-mch  stroke,  free  air  capacity  2640  cubic  feet  per  min- 
ute; one  Ingersoll  Class  "  A  "  22-  and  22^-  by  24-inch  stroke, 
free  air  capacity,  1320  cubic  feet;  one  Ingersoll  20-  and  22^- 
by  24-inch  stroke,  free  air  capacity,  1320  cubic  feet  per 
minute;  and  an  Ingersoll  16-  and  i6j-  by  18-inch  stri^ke, 
free  air  capacity,  698  cubic  feet  per  minute^^,.^^>4^^^£;^^< 

Hudson  Companies'  North  River  Tuimels,  Fifteenth  Stt^et, 
Hoboken,  N.  J.      This  plant  is  located  immediately  opposite 


Fig.  11. — Interior  of  Long  Island  City  Power  House  for  Belmont  Tunnels. 

the  preceding,  working  at  the  other  ends  of  the  same  tunnels 
and  continuing  them  westward  into  the  land.  There  is  one 
compressor  here  which  was  sold  to  the  Hudson  River  Tunnel 
Company  in  1880,  and  overhauled  in  1890,  which  was  still 
doing  good  service  until  the  work  was  finished.  It  is  now 
rated  as  an  Ingersoll  Class  "A",  20-  and  205-  by  30-inch  stroke, 
free  air  capacity  1089  cubic  feet  per  minute.  There  are  also 
two  Ingersoll  Class  "A"  compressors,  22-  and  26I-  by  24-inch, 


APPENDIX  A  201 

free  air  capacity  2686  cubic  feet  per  minute;  and  one  Ingersoll 
duplex  Class  "H"  compressor  16-  and  20J-  by  16-inch  stroke, 
free  air  capacity,  2178  cubic  feet  per  minute. 

Hudson  Companies'  North  River  Tunnels,  Near  Pennsyl- 
vania Station,  Jersey  City,  N.  J.  The  tunnels  here  being  driven 
are  to  enter  New  York  City  near  Cortlandt  Street;  there  is  no 
plant  opposite,  the  tunnels  being  driven  entirely  from  their 
western  ends.  There  are  here  three  Ingersoll  Class  "  HC  " 
cross-compound  steam,  2-stage  air  compressors  for  high  pres- 
sure air,  and  three  Ingersoll  Class  "  H  "  cross-compound  steam 
and  duplex  single-stage  air  compressors  for  the  low-pressure 
air.  The  former  are  14-  and  28-inch  steam  and  24!-  and  141- 
inch  air  by  16-inch  stroke,  free  air  capacity  4710  cubic  feet  per 
minute;  and  the  latter  are  of  the  same  steam  dimensions  with 
air  cylinders  22-^-  by  16-inch,  free  air  capacity,  7920  cubic  feet 
per  minute. 

Hudson  Companies'  No.  4  Plant,  Washington  Street,  Jersey 
City,  N.  J.  This  plant  has  been  employed  upon  land  tunnels 
connecting  the  two  preceding.  It  comprises  two  Rand  Class 
"  B  "  compressors,  cross-compound  steam  cylinders  18-  and 
30-inch,  and  2-stage  air  cylinders  26-  and  15-inch  by  30-inch 
stroke,  free  air  capacity  3686  cubic  feet  per  minute;  and  two 
Rand  Class  "B"  compressors  with  steam  dimensions  as  above 
and  duplex  air  cylinders  23-inch  diameter  by  30-inch  stroke, 
free  air  capacity  5768  cubic  feet  per  minute. 

Summary  of  Tunnel  Plants.  The  total  free  air  capacity 
of  all  the  compressors  here  enumerated  is  191,291  cubic  feet  per 
minute,  which  would  be  represented  by  a  cube  with  a  side  of 
over  57  feet.  The  total  number  of  compressors  is  eighty, 
most  of  them  approaching  the  largest  sizes  built.  The  actual 
horse-power  employed  has  not  been  computed  on  account  of 
the  differences  in  the  air  pressures,  but  probably  is  not  less 
than  40,000.  The  number  of  steam  cylinders  is  one  hundred 
and  twenty  and  the  number  of  air  cylinders,  one  hundred  and 
thirty-eight.  That  these  compressors  have  been  kept  con- 
stantly running,  mostly  night  and  day,  and  generally  at  speeds 
which   would   be   considered   excessive,   is   something   for   the 


202 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


builders,  the  owners  and  the  operators  to  be  proud  of.  What- 
ever delays  have  occurred,  whatever  accidents  have  happened, 
whatever  of  the  unforeseen  has  been  encountered,  the  air  com- 
pressors have  been  always  ready,  always  efficient  and  always 
to  be  rehed  upon. 


Fig.  12. — One  Type  of  Boiler  Used  in  the  New  York  Tunnel  Plants. 


It  will  be  seen  that  the  compressed  air  for  this  tunnel  work 
is  delivered  and  used  at  two  quite  different  pressures,  requiring 
two  different  classes  of  compressors  and  separate  pipe  lines 
for  transmission.  The  low  pressure  air  for  the  shield  work  is 
generally  used  at  pressures  of  between  20  and  30  pounds  and 
the  compressors  are  usually  guaranteed  for  a  maximum  of  50 


APPENDIX  A  203 

pounds.  The  high  pressure  air  for  operating  the  drills  is  required 
to  be  higher  than  the  normal  for  such  work,  as  the  air  from  them 
is  exhausted  against  the  air  pressure  in  the  shield.  The  air 
for  this  service  is  carried  at  pressures  above  loo  pounds  up  to 
140  or  150  pounds,  the  compression  being  2-stage  with,  of 
course,  efficient  intercooling.  Many  of  the  installations  also 
include  aftercoolers,  which  are  found  to  contribute  to  economy 
of  operation,  giving  drier  air  and  reducing  the  volume  during 
transmission  without  any  ultimate  reduction  of  volume  when 
the  air  is  used  at  the  end  of  the  line. 

The  usual  conditions  of  steam  economy  are  insisted  upon 
throughout  these  plants.  Steam  is  carried  at  pressures  up  to 
150  pounds,  the  steam  ends  of  the  compressors  are  generally 
compounded,  and  condensing  apparatus  is  usually  installed 
for  each  entire  plant  whether  the  individual  units  are  com- 
pounded or  not.  The  automatic  regulation  of  the  speeds 
of  the  compressors  according  to  the  varying  demands  of  the  ser- 
vice has  been  a  notable  and  successful  feature. 

Much  the  larger  volume  of  the  air  compressed  has  been  for 
the  low  pressure  service  to  oppose  the  inrush  of  water,  and 
passengers  on  the  East  River  ferries  have  seen  the  water  actively 
boiling  with  the  escape  of  this  air,  so  that  most  of  it  may  in 
a  way  be  said  to  have  been  lost  or  wasted.  Under  the 
most  favorable  conditions  the  use  of  air  in  subaqueous 
tunnels  is  a  very  different  problem  from  that  of  the  vertical 
caisson.  In  the  latter  the  pressure  adjusts  itself  precisely 
to  that  of  the  surrounding  water,  the  air  escaping  under 
the  edge  when  the  pressure  is  at  all  in  excess,  and  the 
compressor  supplying  a  caisson  has  only  to  make  up  for  the 
losses  in  the  air  lock  and  to  renew  the  air  sufficiently  for  safe 
respiration. 

When  the  air  pressure  at  the  top  of  the  tunnel  is  suf- 
ficient to  balance  the  pressure  of  the  water  and  hold  it  back, 
the  air  pressure  at  the  bottom  of  the  tunnel  will  be  five  or  six 
pounds  too  fight;  and  if  the  pressure  is  increased  to  balance 
the  water  pressure  at  the  bottom,  then  it  is  able  to  blow  off 
at  the  top  with  considerable  force,  and  where  the  superincumbent 


204      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

material  is  in  a  soft  or  semi-fluid  condition  the  air  finds  its  way 
through  it  in  all  directions.  The  compressors  in  this  service 
were  constantly  worked  to  their  utmost  in  the  struggle  with 
the  soft  mud  waiting  to  rush  in,  and  an  unstable  equiUbrium 
only  could  be  maintained  at  the  best. — Frank  Richards,  in  Com- 
pressed Air  Magazine,  January,  1908. 


APPENDIX   B 

THE  COMPRESSED    AIR   PLENXM 

The  remarkable  success  which  engineers  have  made  in  driving 
tunnels  under  rivers  and  other  important  waterways  in  various 
parts  of  the  world,  has  led  to  a  serious  consideration  of  employ- 
ing similar  methods  for  estabhshing  subaqueous  passages 
beneath  straits,  bays  and  even  the  ocean  itself.  From  the 
constructional  point  of  view,  there  is  not  the  slightest  doubt 
of  its  feasibility,  for  what  has  been  done  so  satisfactorily  in 
many  cases  can  be  extended  to  a  far  greater  degree. 

At  the  present  time  financial  reasons  would  alone  seem 
to  prevent  the  boring  of  tunnels  between  Europe  and  Africa, 
or  Asia  and  North  America,  since  the  expense  would  be,  perhaps, 
larger  than  the  ultimate  advantages  to  be  secured.  Further- 
more, in  the  face  of  the  diplomatic  relations  existing  between 
world  powers,  such  engineering  feats  appear  to  be  well-nigh 
impossible.  However,  apart  from  this,  engineers  regard  Vv'ith 
confidence  the  proposition  of  sub-ocean  tunneling  because  the 
achievements  already  attained  have  been  due  to  the  develop- 
ment of  the  compressed  air  system.  At  first,  when  this  system 
was  introduced,  its  possibilities  were  only  conjectural,  for  its 
beginnings  were  small  inasmuch  as  it  was  used  for  driving  bores, 
making  foundations  for  bridges  and  wharves  under  river  beds, 
and  in  waterbearing  strata  generally.  But  it  has  developed 
steadily,  until  now  work  is  carried  on  with  safety  and  with 
certainty,  as  regards  its  final  result,  at  depths  up  to  nearly 
1 20  feet  below  high- water  level,  invohing  an  air  pressure  of  40 
pounds  per  square  inch  above  the  atmosphere.  In  fact,  in 
nearly  every  instance  where  water  is  likely  to  be  encountered, 
compressed  air  is  now  adopted,  for  engineers  prefer  to  use  it 
as  a  safeguard  against  any  emergency.     Whether  compressed 

205 


206      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

air  can  be  applied  for  deep-sea  boring  is  still  largely  a  matter 
of  experiment.  Still,  the  shield  system  has  operated  so  accurately 
in  all  cases  with  such  practical  results,  that  its  application 
to  engineering  problems  of  such  magnitude  as  referred  to  above 
is  highly  probable.* 

The  phenomenal  advances  in  the  methods  of  subaqueous 
tunneling  in  the  last  few  years  are  directly  due  to  the  improve- 
ments in  the  means  of  generating,  and  of  operating  with,  com- 
pressed air. 

The  use  of  the  plenum  method  for  tunneling,  and  in  sink- 
ing caissons,  has  become  general  in  submarine  work.  The 
air,  compressed  to  the  required  pressure,  provides  in  itself 
the  power  to  operate  the  drills,  shovels,  pumps,  jacks  and  shields, 
and  all  other  machinery  employed  in  the  tunnels,  as  well  as 
providing  the  necessary  pressure  to  counterbalance  the  weight 
of  water  and  material  through  which  the  tunnel  is  being  driven; 
and  at  the  same  time,  air  that  has  been  used  for  power  is  pro- 
ducing a  constant  ventilation  and  supply  of  fresh  air  to  the 
workmen. 

Air,  when  compressed,  is  the  only  medium  possessing  the 
quaHties  which  are  requisite  in  the  varied  conditions  and  opera- 
tions of  subaqueous  tunnehng.  In  the  East  River  tunnels, 
the  average  total  supply  of  free  air  to  each  heading  while  under 
pressure  was  3550  cubic  feet  per  minute;  this  included  the 
compressed  air  used  for  all  purposes  in  the  headings.  In  blow- 
outs the  maximum  loss  recorded  was  220,000  cubic  feet  of  free 
air  in  ten  minutes.  It  is  probable  that  30  to  40  per  cent  of 
this  loss  occurred  in  the  first  forty-five  seconds,  the  remaining 
loss  being  gradual  till  the  supply  was  increased  to  the  lowered 
pressure. 

The  silt  pressure  was  lower  than  the  hydrostatic  head  at 
the  crown,  but  if  it  became  necessary  to  make  an  excavation 
ahead  of  the  shield,  the  air  pressure  required  was  about  equal 
to  the  weight  of  the  overlying  material,  namely,  the  water  and 
silt.  The  silt  weighed  from  97  to  106  pounds  per  cubic  foot, 
averaged  100  pounds  per  cubic  foot,  and  acted  like  a  fluid. 

*  From  Compressed  Air  Magazine,  June,  1907. 


AITENUIX   B  207 

The  records  of  the  air  supply  proved  beyond  doubt  that 
any  supply  per  man  beyond  2000  cubic  feet  had  no  beneficial 
efifect  upon  health;  on  two  occasions  for  two  consecutive  weeks 
it  ran  as  low  as  icoo  cubic  feet  without  increasing  the  number 
of  cases  of  bends. 

The  amount  of  CO2  in  the  air  was  measured  daily.  The 
average  ranged  between  0.8  and  1.5  parts  per  loco  parts.  In 
exceptional  cases  it  fell  as  low  as  0.3,  and  rose  to  4.0.  The 
temperature  usually  ranged  from  55  to  60  degrees  Fahrenheit, 
which  was  the  temperature  of  the  surrounding  silt;  when 
grouting  extensively  in  the  long  sections  in  rock,  it  varied  from 
85  to  no  degrees  Fahrenheit.  The  pressure  of  air  varied  from 
17  to  37  pounds.  To  enable  the  engine  room  force  to  keep 
a  watch  on  the  air  conditions  in  the  tunnel,  a  half-inch  air 
line  connected  the  working  chambers  with  recording  gages  in 
the  engine  room.  During  the  greater  portion  of  the  work  in 
soft  ground,  a  pressure  was  maintained  which  would  about 
balance  the  hydrostatic  head  at  the  axis  of  the  tunnel.  The 
required  pressure  varied  from  30  to  34  pounds  above  that  of 
the  atmosphere.  In  the  event  of  a  blow,  the  pressure  usually 
dropped  from  2  to  8  pounds  and  it  generally  took  some  hours 
to  restore  the  original  pressure. 

The  rules  observed  for  the  prevention  of  caisson  disease 
were,  that  no  workman  was  allowed  to  enter  the  air  chamber 
without  having  undergone  a  physical  examination,  sound 
physique  being  an  essential  requirement.  The  men  were  required 
not  to  enter  the  air  with  an  empty  stomach,  to  wear  warm 
clothing  on  coming  out,  and  to  drink  hot  coffee.  The  time 
worked  in  the  air  chamber  was  Hmited  to  eight  hours  with 
half  an  hour  for  lunch,  up  to  32  pounds  gage  pressure;  and  two 
spells  of  three  hours  each  with  three  hours'  rest  between,  for 
pressures  from  32  to  42  pounds;  and  two  spells  of  two  hours 
each  for  pressures  greater  than  42  pounds,  with  four  hours' 
rest  between. 

Medical  air  locks  were  installed,  well  warmed  dressing  rooms 
provided  for  the  workmen,  and  covered  gangways  for  access 
to   the  shafts.     Practically  no  cases  of  bends  occurred  until 


208 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


the  air  pressure  reached  29  pounds,  when,  within  a  few  days 
of  each  other,  two  men  died. 

At  30  pounds  pressure,  it  became  customary  to  allow 
one-half  minute  per  pound  of  air  pressure  in  decompression. 
The  lengthening  of  the  decompression  period  to  fifteen  minutes 
reduced  the  number  of  cases  of  bends,  and  no  doubt  prevented 


Fig.  1, — Interior  of  Medical  Air  Lock. 


many  fatal  ones;  but  they  still  occurred.  The  percentage 
of  cases  in  air  pressures  of  31 2  pounds  for  8-hour  shifts  was 
no  greater  than  the  percentage  in  32^  pounds  for  two  3 -hour 
shifts.     It  was,  if  anything,  less  for  the  longer  shift. 

At  atmospheric  pressure,  the  percentage  of  carbon  dioxide 
in  the  alveolar  or  expired  air  is  5.6  per  cent  and  at  a  pressure 
of    2    atmospheres    absolute,    this  is  reduced  to  2.8  per  cent. 


APPENDIX  B  209 

So  the  question  of  the  percentage  of  carbon  dioxide  in  the  air 
of  the  working  chamber  is  not  important  unless  it  approaches 
the  percentage  in  the  air  cells  of  the  lungs.  To  illustrate  this, 
if  the  air-chamber  is  under  an  air  pressure  of  30  pounds,  or  3 
atmospheres  absolute,  the  percentage  of  carbon  dioxide  in  the 
air  cells  is  5.6  divided  by  3,  or  1.86  per  cent;  and  if  the  per- 
centage of  carbon  dioxide  in  the  air  chamber  does  not  exceed 
I  per  cent,  no  ill  effects  will  arise.  This  is  ten  times  as  much 
as  generally  specified,  namely  one  part  in  1000,  and  greatly 
reduces  the  amount  of  compressed  air  necessary  per  man  per 
hour,  which  can  be  calculated  approximately  from  the  follow- 
ing formula: 

„  ,  .    ,    ,  ,  8q  cubic  feet 

Cubic  feet  per  man  per  hour  = ^:^;^ rrrrj- 

^  ^  percentage  CO2  permitted 

Thus,  if  0.04  per  cent  is  the  CO2  in  the   atmosphere,  and 

the  percentage  in  the  tunnel  is  allowed  to  go  up  to  o.io  per  cent, 

80 
the  air  required  per  man  per   hour  equals  ^  t  =  i333   cubic 

feet. 

The  death  rate  due  to  caisson  disease  was  comparatively 
small,  an  average  of  19/100  of  one  per  cent  for  the  whole  of  the 
compressed  air  work.  The  only  recognized  cure  for  caisson 
disease  is  recompression  in  a  medical  air  lock,  followed  by 
slow  decompression.  This  makes  evident  the  advantage  of  slow 
decompression;  and  when  it  is  at  all  possible,  in  future  works, 
regulated  decompression  will  in  all  probability  be  adopted. 

From  "  Caisson  Disease  and  Its  Prevention,"  by  Henry  Japp,  M.  American 
Society  C.E.,  Proceedings  American  Society  C.E.,  December,  1909,  where  the 
subject  is  treated  at  length. 


APPENDIX   C 

THE   USE   OF   COMPRESSED   AIR   IN   TUNNELING 

Since  the  first  recorded  experiments  in  air  compression 
by  Hero  of  Alexandria,  and  the  invention  of  the  air  pump  in 
1650  by  Otto  Von  Guericke,  the  most  decided  advance  in  the 
principles  of  air  compression  are  described  in  the  application 
for  a  patent  in  1829  by  William  Mann,  as  follows:  "The 
condensing  pumps  used  in  compressing  the  air  I  make  of  dif- 
ferent capacities,  according  to  the  density  of  the  fluid  to  be 
compressed — those  used  to  compress  the  higher  densities  being 
proportionally  smaller  than  those  previously  used  to  com- 
press it  at  the  first  or  lower  densities,"  etc.  This  was  the  pre- 
cursor of  the  present  system  of  stage  compression. 

In  1847  ^^  English  patent  was  granted  to  Van  Rathen  for 
the  process  of  cooling  the  air  by  water  in  the  cylinder,  or  by 
surrounding  the  vessel  with  cold  water.  He  also  describes  a 
reservoir  for  storing  air,  a  refrigerator  for  cooling  the  air  after 
its  compression,  and  a  mode  of  heating  the  air  to  give  it  greater 
tension  after  it  is  compressed. 

In  1853,  PiS'tti  submitted  several  projects  to  the  Italian 
ministry  relative  to  the  construction  of  the  Mt.  Cenis  tunnels, 
which  treated  especially  of  the  employment  of  water  power 
to  compress  air  for  a  motor  for  rock  drills  in  driving  the  tunnels 
and  for  running  trains  through  the  tunnel  both  during  and 
after  its  construction.  Previous  to  this,  in  1852,  Colladon  of 
Geneva  filed  his  petition  for  a  patent  in  Italy  for  the  use  of 
compressed  air  in  running  machine  drills  in  a  tunnel.  To 
Colladon  is  said  to  be  due  the  essential  features  of  the  com- 
pressor systems  of  the  Mt.  Cenis  and  St.  Gothard  tunnels. 
The  compressor  systems  of  Mt.  Cenis  were  established,  and  the 
drills  put  to  work,  during  1861.     It  is  stated  that  Colladon, 

210 


APPENDIX  C 


211 


o 
O 

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i 

H 

< 


O 


212      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

as  far  back  as  1828,  proposed  to  B runnel   to  use  compressed 
air  to  keep  the  water  out  of  the  first  Thames  tunnel. 

In  America,  air  compressors  were  first  applied  for  purposes 
of  rock  drilling  at  the  Hoosac  tunnel.  The  first  compressor 
used  at  the  Hoosac  tunnel  consisted  of  four  horizontal  air 
cylinders  set  at  right  angles,  run  by  a  water  turbine  of  120 
h.p.  and  driven  directly  from  a  crank  on  the  upper  end  of  the 
shaft  of  the  turbine.  Of  this  compressor,  ^Mr.  Thomas  Doane, 
Chief  Engineer,  says  in  his  report  for  1866:  "The  air  com- 
pressor of  four  horizontal    cylinders,   13    by    20   inches   each, 


Ingersoll-Rand  Class  "  NF-1  "  Single-stage  Steam-driven  Air  Compressor. 

referred  to  in  my  former  report  as  about  ready  for  use  at  the 
east  end,  has  been  at  work  night  and  day  without  cessation, 
except  on  Sundays,  since  March.  It  was  intended  to  com- 
press air  to  60  pounds  per  square  inch,  and  has  run  up  as  high 
as  85  pounds;  but  as  the  drilling  machines  require  air  at  only 
30  pounds  pressure  it  has  been  run  generally  at  that  pressure. 
It  w^as  intended  for  a  speed  of  120  r. p.m.,  but  as  it  can  easily  sup- 
ply all  our  drilhng  machines,  nine  having  been  the  highest 
number,  at  a  speed  of  70  revolutions,  it  has  not  usually  been 
run  faster.  This  compressor,  making  70  revolutions,  will  fur- 
nish 148.01  cubic  feet  of  air  per  minute,  at  a  pressure  of  42 
pounds." 

In  selecting  an  air  compressor,  the  conditions  under  which 


APPENDIX  C 


213 


it  is  to  operate  are  to  be  carefully  considered,  as  it  is  impossible 
to  design  a  single  compressor  which  will  fit  all  conditions.  The 
most  important  factors  are:  Pressure  desired;  the  character 
of  apparatus  to  be  operated;  the  cost  of  fuel;  allowable  space; 
and  quantity  of  air  required.  Generally  speaking,  economy 
has  not  been  the  most  important  consideration  until  recently. 
The  three  classes  into  which  reciprocating  apparatus  for 
the  production  of  compressed  air  naturally  fall,  and  considera- 
tions of  convenience,  first  cost  and  economy  of  operation,  have 


Ingersoll-Rand  Class  "O"  Duplex  Double  Cross-compound 
Duplex  Air  Compressor. 


resulted  in  the  development  of  certain  distinct  types  of  com- 
pressors, which  may  be  classed  under  the  general  heading  of  self- 
contained  steam  actuated  compressors,  and  those  actuated 
by  some  external  means. 

Both  classes  may  be  simple,  duplex  or  multi-compression 
machines.  Experience,  however,  has  sifted  out  the  best  forms, 
which  are  as  follows: 

(i)  Straight  Line;  that  is,  steam  and  air  cylinders  in  one 
line,  mounted  on  a  continuous  girder  frame.  A 
self-contained,  reliable  type;   a  great  user  of  steam^ 


214  SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

but  a  most  satisfactory  type  when  fuel  is  inexpensive 
and  where  a  large  amount  of  air  is  not  needed; 
usually  single-stage  compressors,  but  often  built  in 
two  or  three  stages. 

(2)  Duplex;    usually  built  with  two  parallel  engines,  con- 

nected by  90-degree  cranks  to  a  single  fly-wheel 
shaft,  with  air  cylinders  behind  each  steam  cylinder. 
Both  steam  and  both  air  cylinders  are  of  the  same 
diameter.  This  type  makes  no  great  pretense  at 
economy,  but  finds  an  extensive  fidd  in  locations 
where  fuel  is  not  high  and  where  simplicity  and  small 
first  cost  are  important,  and  where  considerable  air, 
at  low  pressures  only,  is  desired. 

(3)  Compound;  of  the  same  general  character  as  the  duplex 

except  that  either  or  both  air  and  steam  cylinders 
are  compounded.  In  some  cases  the  engine  may  be 
run  condensing.  This  is,  however,  hardly  necessary 
except  for  very  large  sizes,  where  it  is  far  more  desir- 
able to  use  the  large  class  of  Corliss  type. 

(4)  Corliss  type;   as  implied  in  the  name,  this  class  includes 

compressors  in  which  the  engine  portion  employs 
the  well-known  Corliss  valve  motion.     Such  com- 
pressors, with  few  exceptions,  are  of  the  horizontal 
type,  the  air  cylinder  or  cylinders,  as  the  case  may 
be,   being  placed   tandem   to   the   steam   cylinders. 
They  are  employed  where  the  volume  of  air  desired 
and  the  fuel  conditions  demand  the  most  economical 
form  of  engine.     They  are  usually  compounded,  both 
for  steam  and  air,  and  generally  run  condensing. 
As  air  is  commonly  used  under  the  same  conditions  and 
with  the  same  machinery  that  uses  steam,  the  true  way  of  com- 
paring the  efficiency  of  a  compressor  would  be  to  compare  the 
volume  of  cold  compressed  air  that  the  compressor  will  furnish 
with  the  volume  of  steam  the  compressor  uses  at  the  same  pres- 
sure, to  furnish  the  amount  of  air.     On  this  basis,  the  efficiency 
of  a  straight  line  compressor,  non-compound,  would  be  about 
60    per   cent.;   a   duplex    Corliss   compressor   with    compound 


Al'l'KNDIX  C 


215 


condensing  steam  and  compound  air  cylinders  with  inter- 
cooler,  about  80  or  90  per  cent,  in  cold  air,  of  the  amount 
of  steam  used. 

If  the  properties  of  cold  air  and  steam  are  compared,  the 
comparison  is  all  in  favor  of  air.  The  loss  due  to  condensation 
in  an  exposed  steam  pipe  line  often  amounts  to  from  15  to  30 
per  cent.  This  loss  alone  would  make  the  use  of  air  more 
economical. 

Air  pipe  lines  have  in  different  places  been  laid  for  distances 
of  fifteen  miles  or  more,  but  average  pipe  lines  in  tunnels  and 
around  quarries  run  from  1000  to  10,000  feet. 


IngersoU-Rand  Class  "CH  "  Corliss  Steam  Double  Cross-compound 
Dviplex  Air  Compressor. 


As  a  practical  example  of  what  would  be  required  if  1000 
cubic  feet  of  free  air  compressed  per  minute  to  80  pounds  pres- 
sure were  to  be  carried  a  distance  of  5000  feet,  a  5-inch  pipe  line 
would  show  a  loss  of  pressure  of  about  6  pounds,  and  a  6-inch 
pipe  line  about  2^  pounds,  all  elbows  in  the  pipe  line  increasing 
the  friction.  The  difference  in  the  diameter  of  the  pipes  accounts 
for  the  difTerence  in  loss  of  pressure. 

The  friction  loss  may  be  considered  for  ordinary  purposes 
as  being  proportional  to  the  length  of  pipe  and  to  the  square  of 
the  velocity  of  the  air;  where  the  volume  passing  through  a  pipe 
is  doubled,  the  friction  will  be  about  four  times  as  great. 


216 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


Heating  the  air  by  means  of  a  reheater  increases  the  volume 
from  35  to  50  per  cent;  and  this  increase  in  volume  costs  only 
about  one-sixth  in  cost  of  coal  in  reheating,  as  compared  with 
the  cost  of  coal  in  compressing. 

When  a  compound  condensing  compressor  with  compound 
air  cylinders,  giving  90  per  cent,  in  air  of  the  volume  of  steam 
used,  has  the  air  reheated  before  use,  it  becomes  evident  how  an 


Ingersoll-Rand  "Imperial  X"  Duplex  Steam-driven  Air  Compressor. 


efificiency  20  per  cent  greater  than  if  steam  were  used  direct 
may  be  obtained,  in  addition  to  the  many  advantages  and 
conveniences  in  the  use  of  air. 

From  "  Tunneling,  Explosive  Compounds  and  Rock  Drills,"  by  Henry  S. 
Drinker,  J.  J.  Swann  in  the  Sibley  Journal,  Wm.  Prellwitz  in  Compressed  Air 
Information. 


APPENDIX   D 

SPFXIAL  TYPES   OF  AIR   COMPRESSORS 

Water  Impulse  Compressors.  When  water  power  is  available 
at,  or  within  several  miles  of,  a  plant  where  compressed  air 
is  required,  the  energy  of  the  water  may  be  employed  to  con- 
vert free  air  into  compressed  air  at  any  desired  pressure,  and 
when  piped  to  the  works  may  be  used  for  pumping,  hoisting, 
drilling,  and  many  other  purposes,  with  considerable  success  and 
economy. 

Impulse  wheels  range  in  efficiency  from  85  to  90  per  cent, 
and  insure  the  production  of  compressed  air  energy  at  a  cost, 
per  unit  of  power,  lower  than  by  any  other  method. 

The  sizes  of  water  wheels  used  depend,  of  course,  upon  the 
requirements  of  each  separate  case,  as  to  the  flow  and  head  of 
water.  Water-impulse  compressors  may  be  either  of  the  simple 
straight  line  or  duplex  types.  The  straight  line  form  is 
employed  when  the  demand  for  air  is  light;  this  machine  has 
the  advantage  of  the  straight  line  construction  in  that  it  takes 
up  the  stresses  and  strains  in  direct  lines.  The  duplex  machine 
is  largely  of  service  where  the  demand  for  air  is  considerable, 
and  it  has  the  advantage  of  relieving  strains,  by  dividing  the 
work  equally  between  the  cylinders;  this  machine  is  made 
with  either  simple  or  compound  air  cylinders,  and  when  com- 
pounded a  suitable  intercooler  is  employed  to  remove  the  heat 
of  compression,  as  the  air  passes  from  the  low  to  the  high  pressure 
cylinders. 

"  Imperial  XE  "  Air  Compressor.  The  illustration  on  page 
219  shows  an  Ingersoll-Rand  "  Imperial  XE  "  direct-connected 
cross-compound  2 -stage  electrically  driven  air  compressor,  with 
a  self-starting  synchronous  motor  on  the  shaft.  This  is  one 
of    the   most   recent    developments    in    high-duty   compressor 

217 


218 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


design,  the  direct  motor  drive  having  all  the  advantages, 
as  to  simplicity,  compactness  and  high  efficiency,  which  have 
long  been  recognized  in  direct-connected  engine  driven  electric 
generator  units. 

The  features  of  the  "  Imperial  XE  "  type  are:  "  Imperial 
Corliss  "  air  inlet  valves  on  both  cylinders  and  "  Imperial 
Direct  Lift "     air    discharge  valves;     wholly  enclosed,   dust- 


IngersoU-Rand  Class  "PB"  Direct-water-wheel-driven 
Duplex  Air  Compressor. 


proof  construction;  flood  lubrication  of  all  principal  bearings 
from  the  main  crank  basins,  the  flow  of  oil  being  proportional 
to  the  speed  of  the  machine  and  all  oil  being  returned  to  the 
system;  massive  construction  and  large  bearings.  The  direct 
motor  driven  compressor  unit  of  this  type,  and  of  the  same 
company's  "  PE  "  t\"pe,  return  the  highest  economy  in  power 
driven  compressors.  ^Methods  of  regulation  automatically  pro- 
portion power  to  load  under  all  variations. 


APPENDIX   1) 


219 


The  Taylor  Hydraulic  Air  Compressor  at  Cobalt,   Ontario. 

What  is  undoubtedly  the  largest  single  unit  air  compressor 
in  the  world  is  being  constructed  on  the  Montreal  River  at 
Ragged  Chutes,  about  nine  miles  south  of  Cobalt,  Ontario, 
Can.  This  plant  operates  on  the  now  well-known  Taylor 
system,  where  the  air  is  compressed  by  the  direct  action  of 
falling  water.      The  following  account    may  be  accepted  as 


Ingersoll-Rand  "  Imperial  XE  "  Duplex  Direct-connected 
Electric-driven  Air  Compressor. 


authoritative  in  every  particular,  having  been  prepared  by 
Mr.  C.  H.  Taylor  for  "  Mines  and  jMinerals,"  from  whose  pages 
it  is  here  reproduced,   somewhat  abridged  and  rearranged. 

The  Cobalt  Hydraulic  Power  Company,  Ltd.,  is  a  com- 
mercial organization  formed  for  the  purpose  of  selling  com- 
pressed air  to  the  various  Cobalt  mines.  At  Ragged  Chutes 
there  is  a  drop  in  the  river  of  54  feet  within  less  than  a  quarter 
of  a  mile.  This  entire  head  is  to  be  utilized,  furnishing  5500 
h.p.  and  compressing  40,000  cubic  feet  of  free  air  per  minute 


220      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

to  a  gage  pressure  of  120  pounds,  which  is  automatically 
reduced  to,  and  maintained  at,  100  pounds  when  deUvered  to 
the  various  mines.  The  air  will  be  transmitted  through  nine 
miles  of  20-inch  pipe,  from  the  end  of  which  there  are  two  12- 
inch  branch  pipe  lines.  About  seven  miles  from  the  compressor 
there  is  another  12-inch  branch,  so  that  the  total  length  of  pip- 
ing, 20-,  1 2-,  6-  and  3-inch,  will  be  about  twenty-one  miles. 

In  order  to  prove  that  this  power  would  be  a  great  saving 
over  the  present  cost  for  compressed  air,  about  six  months  were 
spent  in  making  exhaustive  tests  at  a  number  of  the  larger  mines, 
and  the  reports  were  accepted  in  every  case  by  the  managers. 
The  tests  showed  that  mines  could  save  from  one-half  to  one- 
third  by  buying  their  compressed  air  rather  than  producing  it, 
and  at  the  same  time  receive  the  air  at  a  constant  pressure. 
In  addition  to  the  advantages  mentioned,  it  is  to  be  understood 
that  the  air,  being  isothermally  compressed,  is,  of  course,  as 
dry  as  possible,  thus  eHminating  the  troubles  arising  from 
freezing;  further,  there  being  no  oil  used  in  compression,  the 
compressed  air  is  practically  odorless  and  ventilates  the  work- 
ing faces,  which  is  a  distinct  advantage.  The  various  Cobalt 
mines  will  be  piped  independently  of  each  other  and  the  air 
will  be  sold  by  meter  measurement  or  by  the  drill  unit  as  a  basis. 
If  sold  by  meter,  a  rate  of  twenty-five  cents  per  1000  cubic  feet 
of  compressed  air  per  minute  will  be  charged,  the  air  pressure 
being  100  pounds  per  square  inch.  The  company  will  furnish 
in  this  case  an  automatic  reducing  valve,  meter,  and  limit 
valve.  When  air  is  sold  on  the  flat  rate,  the  charge  will  be 
based  on  one  drill  per  shift,  the  charge,  however,  decreasing 
with  an  increasing  number  of  drills.  In  this  case,  the  power 
company  will  supply  the  reducing  and  limit  valves,  no  meter 
being  needed. 

Great  care  has  been  taken  in  the  installation  of  the  pipe 
lines,  to  prevent  leaky  joints  and  strains  on  the  pipe.  In  the 
20-inch  and  12-inch  diameter  pipe  lines,  balanced  expansion 
joints  have  been  placed  at  half-mile  intervals,  and  half-way 
between  each  two  expansion  joints  the  pipes  are  anchored  in 
massive  concrete  piers  to  prevent  their  creeping. 


APPENDIX   D 


221 


After  passing  the  gates  the  water  flows  through  two  16- 
foot  diameter  intake  heads,  one  of  which  is  shown  in  Fig. 
I  at  a.  In  each  of  these  heads  there  are  sixty-six  14-inch 
diameter  pipes  h  set  in  a  steel  disk  c.  Below  the  pipes, 
the  heads  gradually  diminish  in  diameter  until  they  become 
8  feet  4J  inches,  and  from  this  point  they  are  15  feet 
long.      In   this   telescopic   form   the  heads   connect  with   the 


Fig.  1. 

intake  shafts,  which  are  8  feet  6  inches  in  diameter  and  345 
feet  deep,  with  the  orifice  of  the  head  at  the  surface  of  the 
water.  This  arrangement  permits  the  heads  to  be  raised  or 
lowered,  to  conform  to  the  level  of  the  water  in  the  forebay, 
or  the  heads  may  be  raised  above  the  level  of  the  water  by  air 
lifts  d,  thus  cutting  ofl[  the  supply  completely.  The  two  air- 
lift cylinders  d  act  as  governors,  automatically  raising  and  low- 
ering the  heads  which  are  suspended  from  them  by  the  hangers 
e,  thereby  regulating  the  flow  of  water  into  the  intake  pipes  b. 


222 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


according  to  the  demand.  The  head-pieces  were  especially 
designed  to  meet  conditions  due  to  extremely  low  temperatures. 
The  gate  /  is  raised  by  rack  and  pinion,  and  there  is  the  usual 
rack  g  to  prevent  floating  material  from  entering  the  head- 
pipes. 

The  water,  with  the  entrained  air,  flows  through  the  heads 
with  a  descending  velocity  of  from  15  to  19  feet  per  second, 


Fig.  2 


gradually  diminishing  in  the  velocity  of  fall,  owing  to  the  com- 
pression of  the  volume  of  air ;  finally  there  is  a  further  reduction 
in  velocity  owing  to  the  enlarged  section  of  the  last  40  feet  of 
fall,  shown  in  Fig.  2.  By  the  time  the  water  reaches  and  strikes 
the  steel-capped  concrete  diverting  cones  a,  its  velocity  is  so 
diminished  by  the  baffle  from  the  compressed  air  that  there  is 
little  shock. 

The  cones  a  are  for  the  purpose  of  spreading  the  flow  of 
air  and  water,  thereby  bringing  the  air  nearer  to  the  top  of 


APPENDIX  D  223 

the  tunnel.  The  air  being  lighter  than  the  water,  it  rises  to 
the  surface  of  the  water  under  a  pressure  of  120  pounds  per 
square  inch.  The  tunnel  was  made  20  feet  wide,  26  feet  high, 
and  1000  feet  long,  the  latter  for  the  purpose  of  utihzing  the 
total  head  of  the  stream,  although  this  length  was  not  necessary 
in  order  to  give  the  air  time  to  leave  the  water  before  the  latter 
started  up  the  outlet  shaft  b.  As  the  velocity  of  the  water  in 
the  tunnel  is  about  3  feet  per  second,  practically  all  the  air 
will  leave  the  water  in  the  first  300  feet.  The  last  75  feet  of 
the  tunnel  has  the  height  reduced  to  16  feet. 

The  pressure  given  to  the  air  is  due  to  the  height  of  the 
body  of  the  water  in  the  outlet  shaft,  which,  in  this  case,  is  298 
feet  deep  and  22  feet  in  diameter.  The  water  flows  along  the 
tunnel  and  up  the  outlet  to  the  river,  the  difference  in  elevation 
between  the  mouth  of  the  intake  and  the  discharge  tunnels 
being  47  feet.  Near  the  outlet  end  of  the  tunnel  its  height  is 
increased  to  42  feet,  and  at  this  place  two  pipes  are  carried 
through  the  30-degree  riser  c  to  the  uptake  shaft.  One  pipe 
d,  24  inches  in  diameter,  carries  the  compressed  air  to  the  sur- 
face, where  it  is  connected  with  the  20-inch  main  air  pipe  line. 
The  other  pipe  e  is  12  inches  in  diameter  and  has  its  end  sub- 
merged at  a  safe  distance  above  the  roof  of  the  outlet  portion 
of  the  tunnel,  to  act  as  a  blow-off  in  case  the  air  in  the  tunnel 
should  acquire  such  pressure  as  to  force  the  w^ater  below  the 
level  of  the  tunnel  outlet.  If  the  air  were  allowed  to  escape 
up  the  outlet  it  would  lighten  the  column  of  water  in  that  shaft, 
and  the  air  pressure  would  not  be  constant.  The  blow-off 
pipe  ends  at  the  upper  level  of  the  water  in  the  outlet  shaft, 
its  end  remaining  open  to  the  atmosphere.  When  the  volume 
of  air  is  greater  than  the  demand,  the  air  accumulates  in  the 
upper  part  of  the  tunnel,  forcing  the  water  down  and  exposing 
the  lower  end  of  the  blow-off  pipe  e  to  the  compressed  air,  thus 
allowing  a  portion  of  the  water  in  this  pipe  to  drop  back,  thereby 
decreasing  the  weight  of  the  remaining  water  in  this  pipe  to 
less  than  the  pressure  of  the  air.  The  equilibrium  is  now  over- 
come and  the  water  in  the  pipe  is  driven  upward  to  the  surface, 
where  a  most  spectacular  sight  is  witnessed,  as  the  body  of 


224      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

water  is  shot  out  by  the  air  sometimes  to  a  height  of  500  feet. 
The  blow-off  continues  until  the  pressure  of  the  air  in  the  tunnel 
is  sufficiently  reduced  to  again  submerge  the  end  of  the  pipe. 
Water  now  rises  until  an  equilibrium  is  established  between  the 
air  and  the  water  pressure  in  the  tunnel.  The  air  pipe  and  the 
blow-off  pipe  are  packed  in  concrete  the  entire  length  of  the 
30-degree  riser,  in  order  to  seal  them  in  and  prevent  any  escape 
of  air  up  the  outlet  shaft.  Thus  these  arrangements  permit 
the  delivery  of  a  large  body  of  air  at  a  constant  pressure  at  all 
times.     Compressed  Air  Magazine,  June,  1910. 

Lack  of  Oxygen  in  Hydraulic  Air  at  Cobalt.  When  the 
air  from  the  hydrauHc  air  compressing  plant  at  Ragged  Chutes, 
Cobalt  district,  Ontario,  was  first  turned  on  it  was  found  that 
it  was  difficult  to  burn  candles  in  the  mines  where  it  was  used. 
It  was  claimed  that  this  was  due  to  the  absorption  of  oxygen 
by  the  asphalt  with  which  the  inside  of  the  pipes  was  coated, 
and  that  this  effect  would  soon  pass  off.  It  was  soon  found, 
however,  that  hydraulic  air  contains  an  appreciably  less  per- 
centage of  oxygen  than  ordinary  air,  and  analysis  demonstrated 
that  it  contained  only  17.7  per  cent  oxygen,  which  is  3  per  cent 
lower  than  ordinary  air.  This  is  due  to  the  oxygen  going  into 
solution  in  the  water  during  compression,  when  a  pressure  of 
130  to  135  pounds  per  square  inch  is  maintained.  The  lack 
of  oxygen  does  not  apparently  trouble  the  miners,  but  besides 
the  difficulty  experienced  in  keeping  lights,  the  effect  of  the 
gases  from  exploded  dynamite  is  more  serious  than  was  found 
to  be  the  case  with  air  compressed  by  machinery.  Engineering 
and  Mining  Journal.     Compressed  Air  Magazine,  August,  1910. 

Cost  of  Hydraulic  Air  Compression.  The  Taylor  system  of 
air  compression,  adapted  to  the  development  of  waterfalls  of 
moderate  height  and  copious  volume,  has  ehcited  much  favorable 
comment,  and  where  it  has  been  installed  it  has  been  completely 
successful  so  far  as  the  actual  compressing  of  the  air  is  concerned, 
but  the  cost  which  seems  inevitable  in  its  installation  is  not 
so  familiarly  known.  The  following  account  of  one  plant  is 
given  by  Mr.  Geo.  C.  McFarlane  in  Mining  and  Scientific  Press. 

"  The  most   recent   installation  is  a  5000   h.p.  plant  now 


APPENDIX  D  225 

about  completed  at  the  Ragged  Chutes  of  the  Montreal  River, 
nine  miles  south  of  Cobalt,  Ontario.  Work  has  been  in  progress 
on  this  installation  for  three  years  and  for  the  past  year  a  force 
of  200  or  300  men  has  been  employed.  The  Montreal  River 
has  here,  in  about  1000  feet,  a  drop  of  28  feet.  The  power 
people  built  a  concrete  jetty  into  the  middle  of  the  river  and, 
to  protect  the  opposite  bank  from  cutting,  built  a  concrete  wall 
in  a  trench  a  few  feet  back  and  parallel  with  the  bank.  During 
the  high  water  this  summer  (1909)  the  river  current,  thrown 
sideways  by  the  jetty,  gouged  into  the  opposite  bank  as  far  as 
the  concrete  wall  and  partly  undermined  it,  which  illustrates 
one  way  of  how  not  to  attempt  to  raise  the  level  of  a  swift  river. 
"  Just  below  the  jetty,  at  the  head  of  the  rapids,  are  two 
shafts,  steel-hned,  16  feet  in  diameter  and  360  feet  deep.  A 
20-  by  26-foot  tunnel,  1000  feet  long,  connects  these  shafts  with 
the  uprise  shaft  at  the  foot  of  the  rapids.  The  air  is  compressed 
to  140  pounds  and  is  conducted  to  Cobalt  by  a  20-inch  pipe. 
The  pipe  was  made  in  40-foot  lengths,  with  welded  flanges  and 
sliding  expansion  joints  set  in  concrete  pits  every  half  mile. 
Aside  from  the  transmission  pipe  lines  I  would  estimate  the 
cost  of  the  plant  at  the  chutes  as  not  far  from  $1,000,000. 
This  makes  the  cost  per  horse-power  for  installation  about 
$200.00  which  does  not  compare  favorably  with  the  cost  of  an 
ordinary  air  plant.  I  know  of  two  small  plants  that  were  installed 
for  less  than  $90.00  per  horse-power,  including  flume  and  pipe 
line,  as  well  as  wheel  and  compressor."  Compressed  Air  Maga- 
zine, April,  1 9 10. 


APPENDIX   E 

STRAIGHT  LINE  AND   DUPLEX   COMPOUND    AIR    COMPRESSORS 

There  is  nothing  new  about  the  higher  expansion  process, 
as  applied  to  marine  engines,  pumping  plants  and  general  power 
service.  But  while,  in  the  engineering  world,  general  practice 
has  settled  down  to  a  true  appreciation  of  the  practical  value 
of  correct  steam  compounding,  there  still  is  much  to  be  said  on 
this  subject  in  its  relation  to  the  economical  compression  of 
air  and  gas. 

Marine  engines  are  almost  invariably  compound  or  triple 
expansion.  Such  engines  work  under  high  pressure,  operate 
condensing,  and  run  under  a  constant  load.  Compound  steam 
cylinders  are  also  common  on  pumps,  even  when  run  non- 
condensing,  and  with  ordinary  steam  pressures.  But  here 
again  is  the  feature  of  constant  load.  Steam  engines  for  general 
power  purposes  are  usually  compounded  if  the  units  are  large 
and  condensing  is  practicable,  but  in  small  and  medium  sized 
units  it  seems  generally  understood  that,  unless  pressure  is 
high  or  condensation  easily  available,  compounding  is  of  doubtful 
value  because  of  the  great  load  variations. 

In  the  case  of  the  air  compressor,  the  conditions  approach 
those  of  the  first  two  instances  cited,  but  differ  radically  from 
the  latter  instance.  These  conditions  are  such  as  to  make 
the  compounding  of  steam  cylinders  desirable  in  every  sense 
of  the  word,  even  where  steam  pressures  are  only  moderate 
and  condensation  not  always  practicable.  The  discussion 
following  will  make  this  point  more  clear  and  may  throw  a  new 
hght  on  the  subject  of  compressor  economy  to  those  not  intimately 
familiar  with  compressor  practice. 

226 


APPENDIX  E  227 

The  advantages  of  compounding  in  steam  engine  practice 
everywhere  are  so  familiar  as  to  require  not  even  a  repetition 
here,  but  its  special  value  in  air  compressing  practice  seems 
not  to  be  fully  appreciated.  In  view  of  the  number  of  steam 
driven  compressors  in  use  which  are  neither  compounded  nor 
condensing,  it  seems  that  it  is  not  generally  understood  that, 
while  a  saving  of  lo  to  15  per  cent  of  the  power  cost  is  possible 
at  the  air  end  of  the  compressor  by  compounding,  a  saving  of 
about  double  that  percentage  in  fuel  cost,  20  to  30  per  cent, 
is  easily  possible  by  compounding  the  steam  end  of  the  same 
machine.  If  compound  compression  is  economically  practical, 
why  neglect  a  saving  twice  as  great  possible  by  compound  steam 
expansion? 

This  neglect  is  especially  remarkable  in  view  of  the  fact 
that  the  air  compressor  embodies  load  conditions  which  make 
the  compounding  and  condensing  of  steam  cyHnders  even  more 
economically  desirable  than  in  general  steam  engine  practice. 
Compound  steam  driven  air  compressors  can  show  better  results 
than  compound  stationary  engines  for  power  purposes,  and  for 
a  very  simple  reason.  To  get  all  the  economy  possible  from 
the  steam,  it  must  be  admitted  to  the  first  cylinder  in  just  such 
quantity  that  when  it  is  finally  expanded  into  the  low  pressure 
cyhnder,  its  pressure  there  shall  be  such  as  to  avoid  excessive 
expansion  and  consequent  heavy  condensation  losses.  This 
means,  of  course,  the  admission  of  the  same  quantity  of  steam 
per  stroke,  for  each  stroke,  implying  a  cut-off  constantly  fixed 
very  close  to  the  right  point.  This  is  entirely  impossible  with 
the  stationary  engine,  where  the  constant  speed  under  var}ing 
load  must  be  maintained  by  a  constantly  changing  cut-off^ 
this  cut-off  being  automatically  controlled  by  the  governor, 
and  necessarily  having  a  wide  range  to  meet  load  conditions. 
There  can  be  only  one  best  point  of  cut-off,  and  departures 
from  that  necessarily  impair  the  ultimate  economy. 

In  the  case  of  the  air  compressor  the  load  is  constant  per 
stroke;  for  the  same  deHvery  pressure  must  be  maintained, 
and  the  cylinders  can  be  so  proportioned  and  the  cut-off  so 
set  as  to  secure  and  maintain  the  best  results.     The  governins: 


228      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

variations  of  the  steam  driven  compressor  are  as  to  speed  only, 
and,  with  air  pressure  constant,  the  changes  in  speed  are  made 
either  by  a  very  sHght  change  of  cut-off  or  with  a  throtthng 
governor.  In  the  latter  case  the  shght  "  wire  drawing  "  is 
about  offset  by  the  resultant  superheating  of  the  steam.  As 
a  result  of  these  conditions  the  compound  compressor  can  be 
made  to  work  close  to  its  best  economy  at  all  times. 

The  steam  pressure  used  has  an  important  bearing  upon  the 
ultimate  economy.  Within  practical  limits,  the  higher  the 
pressure,  the  better  the  results.  Gage  pressures  of  125  to  150 
pounds  are  now  quite  common  in  new  installations;  but  in  air 
compressor  practice,  steam  compounding  is  advantageous  with 
steam  at  80  pounds  condensing,  or  90  pounds  non-condensing, 
though  this  may  not  be  at  all  true  in  general  power  practice. 
When,  as  is  often  the  case  where  compressors  are  used,  water 
is  costly,  the  smaller  amount  required  by  the  compound  is  an 
argument  for  it;  and  the  ultimate  cost  of  the  arrangement 
is  also  largely  offset  by  the  reduced  cost  of  boiler  installation 
and  operation,  due  to  the  lower  steam  consumption. 

It  is  unnecessary  at  this  point  to  enter  into  a  discussion  of 
the  phenomena  of  the  application  of  power  to  resistance  in 
compressor  work.  It  will  be  enough  to  mention  and  to  draw 
briefly  the  distinction  between  the  two  standard  types  of  air 
compressors,  designated  as  the  straight  line  and  duplex.  In  the 
former,  steam  and  air  cylinders,  whether  simple  or  compounded, 
are  arranged  in  a  straight  line,  and  power  is  applied  to  resistance 
through  the  medium  of  one  long  piston  rod.  In  the  duplex 
machine  there  are  two  elements  set  side  by  side,  each  made 
up  of  a  steam  and  an  air  cylinder,  and  each  element  in  effect 
a  straight  line  machine.  However,  the  cranks  of  these  two 
sections  are  set  at  an  angle  of  90  degrees,  or  one-fourth  part  of 
a  circle,  on  the  shaft.  The  primary  object  of  this  quartering 
crank  arrangement  is  to  secure  a  more  uniform  rotation  effect, 
and  to  improve  the  regulation  qualities  of  the  machine  by 
making  it  easier  to  run  at  slow  speeds  through  the  mutual 
assistance  of  the  two  sides.  The  straight  line  compressor  may 
have  two,  three  or  four  cylinders,  but  they  must  all  be  arranged 


APPENDIX  E  229 

in  a  straight  line  or  "  tandem  "  to  one  another.  The  duplex 
compressor  must  have  four  cylinders. 

It  is  an  interesting  thing  that  when  four  cylinders  are 
adopted  in  a  duplex,  to  secure  a  more  uniform  rotation  effect 
and  to  make  it  possible  to  keep  running  at  the  lowest  speeds, 
the  compounding  of  the  cylinders  helps  to  promote  the  original 
purpose  of  the  duplex  arrangement.  At  the  steam  end,  because 
of  the  higher  terminal  pressure,  the  variation  in  working  pres- 
sure is  less.  The  result  is  that  the  effective  pressure  for  the 
stroke  is  more  uniform  and  continuous,  and  the  rotation  effect 
produced  from  the  beginning  to  the  end  shows  less  difference 
than  when  the  steam  is  used  in  a  single  cylinder.  The  differ- 
ence of  pressures  in  the  low  pressure  cylinder  is  less  for  the  same 
reason. 

Aside  from  this  reduction  in  range  of  cylinder  pressures, 
the  differences  in  temperatures  are  a  powerful  element  in 
economy.  These  two  features  will  be  more  clearly  understood 
by  a  brief  consideration  of  a  specific  case. 

Assume  that  the  initial  steam  pressure  is  145  pounds  gage, 
or  160  pounds  absolute,  and  that  a  condenser  gives  a  terminal 
cylinder  pressure  of,  say,  10  pounds  absolute.  Ignoring  for  the 
sake  of  clearness  the  effects  of  clearance,  condensation,  etc., 
there  are  seen  to  be  sixteen  expansions  of  the  steam.  In  com- 
pound steam  cylinders,  properly  proportioned,  this  means  four 
expansions  in  each  cylinder.  In  the  high  pressure  cylinder,  the 
initial  steam  pressure  will  be  160  pounds  and  the  terminal  40 
pounds;  the  initial  temperature  will  be  363  degrees  and  the 
terminal  267  degrees  Fahrenheit.  The  difference  in  pressure 
is  thus  120  pounds  and  in  temperature  96  degrees.  In  the 
low  pressure  cylinder,  initial  and  terminal  pressures  will  be  40 
and  10  pounds,  respectively,  corresponding  to  temperatures 
of  267  and  193  degrees  Fahrenheit.  The  difference  in  pres- 
sures is  here  30  pounds  and  in  temperatures  74  degrees. 

If  this  expansion  had  been  applied  in  a  single  cylinder, 
the  range  of  pressures  would  have  been  150  pounds  and  of  tem- 
peratures 170  degrees  Fahrenheit.  Evidently  the  use  of  com- 
pound steam  cylinders  in  this  case  reduces,  by  approximately 


230      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

one-half,  the  cooling  effect  to  which  cylinder  walls,  ports,  valves, 
etc.,  were  subjected  by  the  drop  in  temperature  through  expan- 
sion. The  steam  consumption  in  the  former  case  would  have 
been  correspondingly  less,  and  the  effect  of  temperatures  on 
steam  economy  is  apparent.  If  a  condenser  had  not  been  used, 
the  range  of  pressures  and  temperatures  would  not  have  been 
so  great,  but,  relatively,  as  between  compound  and  simple 
cylinders,  the  same  comparison  would  hold. 

Looking  now  at  the  air  end,  the  phenomena  and  advantages 
of  compound  air  compression  are  so  well  understood  as  to  need 
no  extended  discussion  here.  It  will  be  enough  to  emphasize 
the  fact  that  in  the  air  cylinders  inversely  the  same  things  are 
true  of  pressures  and  temperatures  as  have  already  been  noted 
in  connection  with  the  steam  cylinders.  The  result  is  a  reduc- 
tion in  the  differences  of  temperatures  and  pressures  in  the  air 
end,  all  tending  toward  an  improved  operation.  The  cutting 
down  and  transferring  of  the  excessive  uncompensated  pres- 
sures in  the  cylinders  from  the  extreme  ends  of  the  stroke,  and 
their  more  uniform  redistribution  secured  by  this  process  of 
double  compounding,  reduce  the  terminal  and  maximum  stresses 
upon  the  bearings  about  45  per  cent.,  noticeably  improving 
running  conditions,  making  the  lubrication  easy  and  more 
effective,  reducing  wear,  and  giving  greater  durability,  while 
still  dispensing  with  the  necessity  for  close  attention. 

Straight  line  compressors  have  been  made  with  tandem  2- 
stage  air  compressing  cyHnders,  and  even  also  with  tandem 
high  and  low  pressure  steam  cyHnders;  but  these  arrangements 
have  greatly  compHcated  the  machine,  have  increased  its  relative 
cost  for  the  work  it  does,  have  made  all  the  parts  more  inaccessible 
than  before  for  adjustment,  repair  or  replacement,  and  after  all, 
have  left  the  machine,  in  its  actual  running,  defective  in  its 
characteristic  inability  to  run  at  slow  speed,  and  to  get  the 
expected  results  at  any  speed. 

In  the  duplex  machine,  as  compared  to  the  simple  straight 
Hne  type,  while  there  is  a  simplification  by  a  reduction  of  the 
number  of  parts  as  regards  fly-wheel,  crank  shaft  and  connecting 
rods,  there  are  four  cyHnders  in  place  of  two.     But  here  is 


APPENDIX  E  231 

where  one  of  the  most  important  of  the  advantages  of  the 
duplex  machine  is  found.  It  happens  that  this  very  arrange- 
ment at  once  provides  the  possibiHties  for  the  best  economy 
both  in  the  development  of  the  power  from  the  steam  and 
in  the  application  of  the  power  to  the  compression  of  the  air, 
simply  by  virtue  of  its  four  cylinders.  To  use  steam  with 
the  best  economy,  in  this  line  of  service,  high  steam  pressure, 
compound  steam  cylinders,  and  a  condenser  should  be  used. 
These  conditions,  except  the  latter,  may  be  provided  for  in  new 
installations;  the  latter  depends  upon  the  water  available. 
To  compress  the  air  to  the  usual  pressures  and  with  the  least 
expenditure  of  power,  compound  air  cylinders  with  an  efficient 
intercooler  between  must  also  be  provided.  An  economical 
air  compressor  of  the  present  day,  cannot,  therefore,  have  less 
than  two  steam  and  two  air  cylinders ;  and  if  the  duplex  machine 
thus  insists  upon  four  cylinders,  it  insists  only  upon  one  of  the 
most  important  conditions  of  practical  economy  in  air  compres- 
sion. If  it  insists  on  a  larger  floor  space,  it  distributes  itself  so 
well  as  to  fully  offset  this  factor  by  its  better  "  get-at-ableness." 
The  duplex  compressor  makes  possible  the  compounding 
of  the  cylinders  either  at  the  air  or  steam  end,  or  both,  without 
additional  comphcation.  The  cylinders  are  there,  and  in  the 
precise  relative  conditions  most  suitable  for  compounding. 
Duplex  compressors  may  be,  and  are,  actually  made  either 
duplex  steam  and  duplex  air,  duplex  steam  and  compound  air, 
compound  steam  and  compound  air,  or  compound  steam  and 
duplex  air.  The  third  arrangement  is,  of  course,  the  ideal 
combination  for  satisfactory  and  economical  air  compression, 
when  steam  and  air  pressures  are  not  too  low.  The  location 
of  the  cylinders  and  other  parts  relative  to  each  other  is 
precisely  that  most  convenient  for  locating  and  connecting  steam 
receivers,  air  intercoolers,  aftercoolers,  and  other  appurtenances. 
The  attitude  of  the  duplex  machine  is  to  invite,  to  make  easy, 
and  to  promote  the  best  practice  in  air  compression.  The 
attitude  of  the  straight  hne  machine,  on  the  other  hand,  is 
just  as  distinctly  to  make  difficult,  and  in  some  details,  impossible, 
the  same  advanced  and  most  approved  practice. 


232      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

It  is  really  a  striking  array  of  advantageous  features  which 
can  be  brought  out  in  favor  of  the  duplex  type  of  air  com- 
pressor. The  following  may  be  recalled  among  them:  Greater 
economy  in  steam  consumption;  gains  by  compounding  both 
steam  and  air  cylinders;  the  maintenance  of  a  more  uniform 
air  pressure;  the  delivery  of  dry  air;  automatic  control  and  effi- 
cient lubrication;  reduced  leakage  by  the  partial  balancing  of 
pressures;  low  friction  of  valves  and  pistons;  sustained  adjust- 
ment and  tightness  of  vital  parts.  These  may  easily  result 
in  a  saving  of  30  to  40  per  cent  over  the  simple  straight  hne 
machine,  and  of  15  to  20  per  cent  over  the  double-compound 
straight  line.  Then  the  reliability  and  perfect  accessibility 
of  every  part,  and  the  saving  in  supervision  and  maintenance, 
are  also  to  be  considered  in  its  favor.  For  the  straight  line 
it  can  be  said  that  the  first  cost  is  perhaps  less,  the  foundations 
required  are  less  expensive,  and  the  space  occupied  is  small. 
The  saving  in  operating  the  duplex  machine  will  really  cover 
the  difference  in  these  costs  many  times  over  and,  before  long, 
entirely  pay  for  the  machine. 

Figures  will  actually  show  that  the  difference  in  the  first 
cost  of  the  machine  and  its  installation  is  returned  in  a  few 
months  without  any  but  the  ordinary  conditions  as  to  fuel 
and  labor  costs. 

Take  an  average  case  in  which  the  power  consumption  is 
but  500  cubic  feet  of  free  air  per  minute,  compressed  at  sea 
level  to  90  pounds  gage.  In  a  single  stage  compressor  this 
will  require  94  indicated  horse-power;  in  a  2-stage  machine, 
81  indicated  horse-power.  A  straight  hne  compressor  of  this 
size  is  usually  operated  with  a  simple  steam  cyHnder;  and  while 
such  machines  are  usually  equipped  with  Meyer  gear  permitting 
economical  cut-off,  yet  the  practical  running  conditions  of  a 
straight  line  are  such  that  not  one  out  of  a  hundred  are,  in 
actual  service,  run  at  less  than  five-eighth  to  three-quarter 
cut-off.  This  is  a  fact  of  experience  and  its  result  is  that  straight 
line  machines  of  this  size  take,  in  every-day  service,  from  40 
to  50  pounds  of  steam  per  horse-power  hour,  and  every  well- 
informed  engineer  knows  that  they  will  require  on  an  average 


APPENDIX  E  233 

of  45  pounds  of  steam  or  water  per  horse-power  hour.  The 
duplex,  having  no  ''dead  center,"  can  be  run  conveniently  at 
short  cut-offs;  and  in  ordinary  compressor  service,  small  units 
and  moderate  steam  pressures,  duplex  compound  steam  cylinders 
will  require  about  28  pounds  of  steam  per  horse-power  hour, 
non-condensing. 

These  relative  figures  are  as  fair  to  one  as  to  the  other;  not 
the  best  that  can  be  done,  but  what  can  actually  be  expected 
under  ordinary  conditions  for  a  term  of  years. 

An  average  boiler  plant  will  not  do  better  than  7  pounds 
of  water  evaporated  per  pound  of  coal  burned.  A  boiler 
horse-power  is  rated  as  30  pounds  of  steam  evaporated  per  hour. 
These  are  average  figures,  and  comparisons  based  on  them  are 
safe  and  fair  to  all. 

Results  in  the  present  case  may  be  tabulated  thus: 

Simple  air  and  simple  steam:  94  indicated  horse-power; 
multiplied  by  45,  equals  4230  pounds  of  steam  per  hour;  divided 
by  30,  equals  141  boiler  horse-power. 

Two-stage  air  and  simple  steam:  81  indicated  horse-power; 
multiplied  by  45,  equals  3645  pounds  of  steam  per  hour;  divided 
by  30,  equals  122  boiler  horse-powTr. 

Duplex  2-stage  air  and  compound  steam:  81  indicated  horse- 
power; multiplied  by  28,  equals  2268  pounds  steam  per  hour; 
divided  by  30,  equals  76  boiler  horse-powder. 

Saving  by  compounding  air  end  alone  (straight  fine  or 
duplex):  13  indicated  horse-power;  585  pounds  of  steam  per 
hour,  19  boiler  horse-power. 

Saving  by  compounding  steam  end  alone  (duplex  cross- 
compound  steam  simple  air):  1377  pounds  of  steam  per  hour; 
46  boiler  horse-power. 

Saving  by  compounding  steam  and  air  (duplex  double- 
cross-compound  only):  13  indicated  horse-power;  1962  pounds 
of  steam  per  hour;  65  boiler  horse-power. 

These  figures  alone  are  enough  to  prove  the  case,  but  the 
buyer  of  machinery  thinks  in  dollars  and  cents  rather  than  in 
horse-power.  He  is,  to  be  sure,  interested  in  knowing  that  the 
duplex  compound  is  "  more  economical  of  power,"  but  he  knows 


234      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

that  "  it  costs  more  "  than  the  straight  hne;  and  even  a  full 
knowledge  of  the  fact  that  the  straight  Hne  "  double-compound  " 
is  mechanically  inferior  to  the  duplex  or  "  double-cross-com- 
pound "  may  not  overcome  his  financial  scruples. 

But  a  complete  compressor  plant  includes  boilers  and 
auxiharies  as  well  as  the  compressor;  and  boilers  cost  money, 
besides  having  a  voracious  appetite  for  coal.  It  has  been 
demonstrated  that  a  "double-compound"  straight  line  is  not 
a  satisfactory  machine;  so  further  comparisons,  reduced  to 
money  values,  may  be  based  on  a  simple  steam  2-stage  straight 
hne  and  a  "  double-compound  "  of  duplex  type. 

To  use  this  straight  Hne  machine,  46  additional  boiler  horse- 
power, with  larger  piping,  auxiharies,  etc.,  must  be  purchased. 
The  buyer,  referring  to  his  catalogue  table,  will  see  81  h.p. 
noted,  but  will  not  notice  that  this  is  indicated  horse-power, 
and  at  a  rating  of  only  30/45,  or  two- thirds  of  the  boiler 
horse-power  required.  So  he  will  probably  buy  a  90  h.p.  boiler, 
force  it  up  to  122  h.p.,  and  then  wonder  why  it  fires  so  hard. 
This  same  inference  made  in  buying  a  "  double-compound  " 
would  have  resulted  in  getting  a  good,  easy-firing  boiler,  prob- 
ably never  loaded  to  its  full  capacity.  The  simple  steam 
straight  Hne,  therefore,  must  be  charged  up  with  the  cost  of  46 
additional  boiler  horse-power,  with  necessary  auxiliaries.  If 
their  price  installed  is  put  at  the  moderate  figure  of  $10.00  per 
horse-power,  not  including  cost  of  auxiliaries  and  larger  piping, 
there  is  a  total  of  $460.00,  which,  credited  to  the  first  cost  of 
the  duplex  double-compound,  does  not  make  the  latter  look  so 
dear  after  all.  In  this  particular  size  of  compressor  it  will, 
probably,  more  than  cover  the  difference  in  price  of  the  two 
types.  These  are  installation  charges  appearing  in  the  items  of 
"  first  cost." 

Looking  now  at  the  operating  charges,  it  will  be  noted 
that  1377  pounds  less  water  per  hour  is  required  by  the  duplex 
compound.  This  is  1650  gallons  per  lo-hour  day.  In  some 
places  water  charge  is  a  serious  item;  at  30  cents  per  thousand 
gallons  this  compressor  saves  in  water  about  50  cents  a  day, 
or  $150.00  per  year  of  300  days.     When  water  is  bad,  the  less 


APPENDIX  E  235 

there  is  to  be  handled,  the  less  boiler  repairs  involved.     In  a 
larger  plant,  the  labor  of  a  fireman  may  also  be  saved. 

The  value  of  the  water  saved  is  important,  but  the  amount  >  / 
of  coal  otherwise  needed  to  evaporate  this  extra  water  is  still  |  ( 
more  important.     At  i  pound  of  coal  per  7  pounds  of  water 
evaporated,  this  1377  pounds  would  require  197  pounds  of  coal 
per  hour,  or  1970  pounds  per  day  of   10  hours.     With  coal  at      I 
$4.00  per  ton,  this  is  $3.94  per  day  or  $1182.00  per  year  of  300  \ 
lo-hour  days.      The  amount  saved  by  the  use  of  the  duplex      \ 
cross-compound  in  fuel  and  water,  therefore,  is  $1332.00  per  ( 
year.     In  five  years  this  amounts  to  $6660.00;   and  if  the  plant  .  | 
runs  double-shift  the  figure  is  doubled.     Further,  as  these  figures 
are  based  upon  only  500  cubic  feet  capacity,  it  can  be  estimated  *  | 
approximately   for   larger   volumes.     For   example,    750   cubic  • 
feet  equals  one  and  one-half  times,  1500  cubic  feet,  three  times  »  • 
these  figures,  etc. 

Where,  now,  is  the  economy  of  "  the  cheaper  machine?" 
Even  with  coal  at  $2.00  per  ton,  or  only  half  the  figure  assumed 
above,  the  saving  per  year  in  fuel  and  water  appears  at  $741.00; 
and  the  duplex  compound  is  obviously  the  thing,  for  this  amount 
will  more  than  overbalance  the  difference  in  cost  between  the 
two  types.  Even  at  this  fuel  rate  its  total  first  cost  would  be 
saved  in  a  few  years;  it  would  pay  to  throw  out  at  once  a  less 
efficient  machine.  When  coal  is  at  all  expensive,  it  is  evident 
that  the  buyer  should  go  on  to  the  most  refined  Corliss  type  of 
compressor,  running  on  only  about  one-half  the  fuel  required 
by  even  the  good  duplex  double-compound  used  in  the  example — 
and  500  cubic  feet  per  minute  is  not  a  large  machine. 

It  must,  however,  be  kept  in  mind  that  to  secure  these 
savings  it  is  not  enough  that  a  compressor  be  of  the  "  double- 
compound  "  type;  but  it  must  be  a  thoroughly  high-class  and 
really  economical  machine,  well  and  properly  designed,  and 
well  built.  As  there  are  good  watches  and  cheap  watches, 
so  are  there  degrees  of  quahty  in  all  things.  As  a  matter  of 
fact,  a  really  high-class  straight  line  compressor  has  been  shown 
by  accurate  tests  actually  to  deliver  its  output  of  air  at  less 
fuel  cost  than  duplex  compounds  which,  on  the  outside,  bear 


236      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

the  appearance  of  economical  design,  and  are  even  sold  under 
"  guarantee."  Guarantees  are  of  little  protection,  for  once 
the  expenses  of  foundations,  piping,  installation,  etc.,  are 
incurred  and  the  work  has  become  dependent  upon  the  continued 
use  of  the  air,  tests  are  not  made  once  in  a  thousand  times;  a 
condition  exists  of  which  the  average  manufacturer  is  quite 
willing  to  take  advantage  even  with  impossible  guarantees. 
If  economy  is  really  wanted,  it  can  safely  be  expected  and 
maintained  only  in  constructions  of  the  highest  standard. 
— Lucius  I.  Wightman,  E.E. 


APPENDIX   F 

COMPOUND   AIR   COMPRESSION 

It  is  well  known  that  the  heating  of  air  produces  an  increase 
in  its  volume.  This  is  true  whatever  the  source  of  the  heat. 
The  heat  produced  in  a  cylinder  by  compression  acts  to  expand 
the  air  in  that  cyHnder,  whatever  may  be  the  speed  or  rate  of 
compression.  In  effect,  this  is  equivalent  to  an  increase  in  the 
volume  of  air  being  compressed  and  delivered.  This  in  turn 
calls  for  an  increase  in  the  power  to  compress  this  apparently 
added  volume  of  air;  or,  to  put  it  differently,  the  heat  of  com- 
pression, in  increasing  the  volume  of  air,  makes  it  necessary 
to  carry  the  air  to  a  higher  average  or  mean  effective  pressure 
in  the  cyHnder  in  order  to  secure  finally  the  required  volume  of 
air  at  the  required  pressure,  after  its  temperature  has  fallen 
to  that  of  the  surrounding  atmosphere.  Looking  at  it  in  this 
way  also,  there  is  seen  to  be  an  excess  of  power  required  to  meet 
the  extra  resistance  mentioned. 

A  consideration  of  these  facts  suggests  that  if  some  means 
be  provided  for  removing  this  heat  of  compression  as  fast  as 
produced,  there  will  be  an  important  reduction  in  the  power 
required  to  raise  a  given  weight  or  volume  of  air  to  a  given 
pressure. 

When  air  is  compressed  in  a  cylinder  without  any  attempt 
whatever  to  remove  the  heat  produced,  the  compression  is  known 
as  "  adiabatic."  When  compression  is  carried  on  in  such  a  way 
that  heat  is  removed  as  fast  as  produced,  the  compression  is 
called  "  isothermal."  In  the  first  case  the  air  dehvered  under 
pressure  will  be  at  the  high  terminal  temperature  correspond- 
ing to  that  pressure.  In  the  second  the  compressed  air  will 
have  the  temperature  at  which  it  entered  the  cylinder.  The 
first  kind  of  compression  is  the  one  which  all  pneumatic  engineers 

237 


238      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

seek  to  avoid;  the  second  is  the  impossible  ideal.  The  actual 
results  secured  in  the  best  compressors  are  intermediate  between 
these,  but  nearer  to  the  adiabatic. 

Other  things  being  equal,  the  economy  of  an  air  compressor 
is  proportional  to  the  degree  in  which  the  heat  of  compression 
is  removed  as  developed.  Compressor  efficiency,  therefore, 
may  be  said  to  depend  upon  the  effectiveness  of  the  cooling 
devices  adopted,  provided  what  is  gained  here  is  not  elsewhere 
wasted  in  whole  or  part.  After  long  experience,  bitter  alike 
to  makers  and  users,  modern  practice  in  compressor  design 
recognizes  only  two  practical  methods  of  removing  the  heat 
of  compression,  viz.,  jacket  cooling  and  intercooling.  These 
will  be  considered  in  order. 

Jacket  coohng  seeks  to  remove  the  heat  of  compression, 
as  it  arises,  through  the  cylinder  walls  which  are  kept  at  a  low 
temperature  by  cold  water  circulaing  in  a  surrounding  jacket. 
A  brief  consideration  of  the  conditions  will  show  that  jacketed 
barrel  coohng  alone  can  be  only  a  partial  and  very  unsatis- 
factory solution  of  the  problem. 

With  the  piston  at  the  beginning  of  its  stroke,  the  maximum 
cold  cyhnder  surface  is  exposed  and  the  cylinder  is  filled  with 
air  at  its  lowest  pressure  and  temperature.  As  the  piston 
advances,  pressure  and  temperature  increase,  while  the  exposed 
area  of  cooling  surface  diminishes;  and  when  the  maximum 
pressure  and  temperature  are  attained  near  the  end  of  the  stroke, 
there  is  practically  none  of  the  cylinder  walls  exposed  except 
on  the  other,  or  intake,  side  of  the  piston;  and  if  the  head,  too, 
is  jacketed,  it  alone  remains  to  exert  any  coohng  influence. 
Furthermore,  throughout  the  stroke  only  the  outside  layer  of 
the  air  can  be  in  contact  with  the  cold  surface  and,  air  being  a 
poor  conductor  of  heat,  none  of  the  heat  from  the  interior  of  the 
air  volume  is  absorbed  in  the  cooling  water.  Cyhnder  jacketing 
is  advisable  and  even  essential,  in  keeping  the  metal  of  the  work- 
ing parts  at  a  low  temperature,  preventing  the  coking  of  lubricant 
upon  the  cylinder  walls,  and  other  evils  of  a  hot  machine.  But 
it  cannot  of  itself  be  considered  as  an  adequate  solution  of  the 
problem  of  cooling  during  compression. 


APPENDIX  F  239 

However,  in  those  constructions  involving  the  use  of  a  piston 
inlet  tube  and  valve,  not  only  the  barrels,  but  the  heads  and  inlet 
valves,  too,  are  chilled;  and  the  piston  and  tube  themselves 
are  kept  relatively  very  cool.  Thus  the  air  enters  through 
a  cold  passage,  is  in  contact  on  all  sides  with  cold  metal  through- 
out the  stroke,  and  the  maximum  effect  obtainable  from  jacket- 
ing alone  is  secured. 

If,  at  several  points  in  the  stroke,  the  piston  should  be 
stopped  for  a  moment  and  the  air,  already  partially  compressed 
and  heated,  be  withdrawn  long  enough  to  be  cooled  by  some 
external  means  to  its  initial  temperature,  and  then  returned 
to  the  cylinder  to  be  further  compressed,  it  is  evident  that  a 
fairly  uniform  temperature  could  be  maintained  in  the  air 
volume  throughout  the  range  of  pressures  from  initial  to  ter- 
minal. The  result  would  in  effect  be  nearly  that  of  isothermal 
compression.  Evidently  mechanical  considerations  forbid  in 
practice  such  repeated  starting  and  stopping  of  the  piston; 
but  the  same  results  may  be  secured  by  carrying  on  the  proc- 
ess of  compression  in  several  cylinders,  in  the  first  of  which 
a  certain  low  pressure  is  reached  and  the  air  at  this  pressure 
discharged  through  a  cooling  device  to  a  second  cylinder;  there 
it  attains  a  still  higher  pressure  and  is  discharged  through 
another  cooler  to  a  third  cylinder  for  a  further  compression; 
and  so  on,  until  the  required  terminal  pressure  is  secured.  Such 
a  process  developed  to  a  practical  working  basis  is  the  "  com- 
pound "  method  of  compression  in  multi-stage  cylinders  which 
has  to-day  become  practically  standard  in  air  compressor  work 
for  the  higher  pressures. 

Theoretically,  there  is  a  gain  in  compound  compression, 
whatever  the  pressure.  But  with  low  pressures  the  saving  is 
so  small  as  to  be  offset  by  the  greater  expense  and  complica- 
tion involved  in  several  cylinders  and  the  losses  unavoidable 
in  the  operation  of  added  parts.  After  extended  experience, 
makers  of  air  compressors  have  fixed  upon  70  to  100  pounds 
gage  as  the  maximum  terminal  pressure  which  can  be  best 
attained  in  simple  cylinders;  and  for  pressures  from  75  pounds 
up,  they  have  adopted  compound  compression  in  2-,  3-  and 


240      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

4-stage  machines,  the  number  of  stages  increasing  with  the 
pressure.  At  high  altitudes,  however,  with  large  volumes  and 
expensive  fuel,  this  dividing  line  may  come  at  a  lower  pressure. 
It  is  elastic  and  depends  somewhat  on  the  conditions. 

In  a  compound  air  compressor,  correctly  designed,  the 
cylinder  ratios  are  such  that  the  final  temperatures  and  mean 
effective  pressures  are  equal  in  all  cylinders,  and  all  pistons  are, 
therefore,  equally  loaded.  The  air  compressed  in  the  first 
cylinder  to  a  pressure  determined  by  the  cylinder  ratio  is 
discharged  through  the  outlet  valves  to  an  intercooler,  where 
it  is  split  up  into  thin  streams  passing  over  cold  surfaces.  The 
best  practice  involves  a  nest  of  tubes  through  which  cold  water 
circulates,  and  over  and  between  which  the  stream  of  air  passes, 
complete  breaking-up  and  subdivision  of  the  stream  being 
secured  by  baffle-plates  and  the  tubes  themselves.  In  cases 
of  very  high  pressure  the  air  may  pass  through  the  tubes,  for 
structural  reasons.  A  properly  designed  intercooler  having 
sufficient  cooling  area  for  the  volume  of  air  may  reduce  the  tem- 
perature of  the  air  compressed  in  the  first  cylinder  to  at  least 
outgoing  water  temperature. 

From  the  intercooler  this  air,  entering  the  second  cylinder 
cold,  is  compressed  to  a  higher  pressure  and  again  reaches  a 
temperature  about  the  same  as  that  attained  in  the  first  cylin- 
der. In  2 -stage  machines  this  air  will  be  discharged  directly 
to  the  receiver  without  further  cooling,  unless  conditions  are 
such  as  to  render  advisable  the  use  of  an  aftercooler.  In  3- 
stage  machines  the  second  cylinder  will  be  known  as  the  inter- 
mediate, from  which  the  air  will  pass  to  the  second  intercooler, 
undergo  a  second  reduction  of  temperature,  and  enter  the 
third  cy finder  for  final  compression  to  required  pressure. 

It  is  seen  that  multi-stage  compression  is  in  effect  identical 
with  that  theoretical  process  suggested  above,  in  which  the 
compressing  piston  was  stopped  and  the  air  cooled  at  intervals 
during  the  stroke.  The  maximum  cooling  effect  and  saving 
is  secured  by  making  the  intercoolers  of  ample  proportions 
and  providing  for  the  spfitting-up  of  the  air  stream  into  thin 
sheets  exposed  to  cooling  action. 


APPENDIX  F  241 

The  discussion  thus  far  has  dealt  with  the  theory  of  com- 
pound air  compression,  the  conditions  encountered,  and  the 
means  adopted  in  the  best  practice  for  meeting  these  conditions. 
General  statements  of  the  gains  secured  by  compounding  have 
been  made.  It  remains  to  discuss  in  detail  some  of  the  more 
important  and  specific  advantages  arising  from  stage  com- 
pression. 

The  table  appended  (see  page  347)  gives  the  percentage  of 
work  lost  in  the  heat  of  compression  in  one,  two,  three  and  four 
stages,  at  various  pressures.  In  these  figures  no  account  is 
taken  of  jacket  cooling,  for  the  reasons  already  stated;  nor  is 
any  allowance  made  for  certain  inevitable  mechanical  losses. 

Taking  a  specific  example,  the  saving  by  compounding  strik- 
ingly appears.  Assume  that  a  volume  of  compressed  air  equiv- 
alent to  100  final  effective  horse-power  is  be  delivered  at  a 
pressure  of  100  pounds.  Referring  to  the  table,  in  column  two 
the  theoretical  percentage  of  lost  work  in  i -stage  compression 
is  given  at  36.7  per  cent;  but  because  there  is  bound  to  be  some 
radiation  of  heat,  this  value  of  36.7  per  cent  will  not  be  found 
in  practice,  and  30  per  cent  may  be  assumed  as  a  good  practical 
value  for  the  loss  under  average  conditions.  On  this  basis  it 
is  found,  in  the  present  case,  that  to  deliver  100  available  horse- 
power in  compressed  air  at  100  pounds  pressure  by  i -stage  com- 
pression, there  will  be  required  130  indicated  horse-power. 
Looking  now  at  column  four  of  the  table,  the  percentage  of  loss 
in  2-stage  compression  at  this  pressure  is  found  to  be  16.9  per 
cent,  which  is  very  close  to  the  value  which  will  be  found  in 
practice.  Applying  this  value,  it  is  seen  that  to  deliver  the 
equivalent  of  100  effective  horse-power  in  air  at  100  pounds 
pressure  by  2-stage  compression,  about  117  indicated  horse- 
power will  be  required.  In  this  case,  as  between  single  and 
2-stage  compression,  we  have  a  direct  saving  of  13  indicated 
horse-power,  or  10  per  cent.  Referring  to  column  six,  the  per- 
centage of  loss  at  100  pounds  pressure  in  3-stage  compression 
appears  at  1.09  per  cent,  showing  in  indicated  horse-power 
required  in  this  case.  Comparing  this  with  the  power  required 
for  the  same  work  in  single-stage  compression,  the  saving  appears 


242      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

as  19  indicated  horse-power,  or  14.6  per  cent.  Considering  the 
compression  of  the  same  volume  to  the  same  pressure  in  four 
stages,  the  percentage  of  loss  is  seen  to  be  7.8  per  cent  from 
column  eight,  implying  an  appHed  power  of  108  indicated  horse- 
power. In  this  case  the  saving,  as  compared  to  single-stage 
compression,  is  22  horse-power,  or  16.9  per  cent. 

From  these  gains  something  must  be  allowed  for  the  fric- 
tion of  extra  mechanical  parts  and  of  the  air  through  additional 
sets  of  ports,  valves,  coolers,  etc.  More  especially  is  this  true 
when  the  machine  belongs  to  that  class  of  machine  termed 
"  compound  ''  by  courtesy,  attractive  in  price  through  frugal 
designing,  in  which  small  coolers,  insufficient  valve  area, 
the  use  of  a  hot  discharge  port  for  the  air  intake,  small  ports, 
etc.,  are  all  antagonistic  to  economy. 

ReHable  and  repeated  tests  show  that  such  machines  may 
actually  require  10  to  15  per  cent  more  power  per  cubic  foot 
of  air  really  deHvered  than  some  well-designed,  simple,  single 
cylinder  types.  No  more  cylinders  are  required  for  the  com- 
pound than  for  the  simple  machine,  in  duplex  constructions. 
Yet,  here,  too,  the  economy  expected  is  only  realized  from 
high-class  designs  generously  proportioned,  and  fitted  with  large 
coolers  and  the  other  essential  refinements  of  good  practice. 

When  compression  is  carried  on  in  a  single  cylinder,  the 
difference  in  the  pressures  at  the  beginning  and  end  of  stroke 
is  the  total  difference  between  initial  and  terminal  pressures, 
implying  a  great  variation  in  strains  on  the  driving  mechanism 
and  the  structure  of  the  machine.  The  greatest  strains  come 
near  the  end  of  the  stroke  and  are  almost  instantly  relieved 
when  the  inlet  valves  open.  Thus  the  terminal  stress  on  a 
20-inch  cylinder  having  314  square  inches  area  at  100  pounds 
pressure  will  be  31,400  pounds  or  nearly  16  tons.  At  100 
revolutions  this  stress  is  repeated  200  times  per  minute  and 
demands  a  very  rugged  construction.  This  is  a  condition 
not  conducive  to  easy  operation  in  any  but  the  most  massively 
proportioned  compressors.  In  compound  compression,  on  the 
other  hand,  the  difference  between  initial  and  terminal  pres- 
sures in  each  cylinder  is  but  a  fraction  of  the  total  range  of 


APPENDIX  F  243 

pressure.  The  pressures,  furthermore,  are  partially  balanced 
in  the  several  cylinders.  The  working  strains  on  valves  and 
other  parts  are  consequently  greatly  diminished,  resulting  in 
a  greatly  reduced  wear  and  liability  to  breakage,  and  securing 
free  lubrication  and  a  noticeable  improvement  in  the  smooth, 
easy  operation  of  the  machine.  These  are  all  facts  which 
contribute  to  continuous  and  satisfactory  service,  with  the 
least  possible  adjustment  and  attention. 

As  a  matter  of  fact,  compounding  the  air  cylinders  transfers 
so  much  of  the  load  from  the  later  to  the  earlier  part  of  the 
stroke  that  the  maximum  terminal  stress  on  bearings  is  reduced 
fully  45  per  cent  over  those  in  single  stage  compression;  in  the 
above  case,  from  3140  "  ton  minutes  "  to  1727,  obviously  a  much 
easier  proposition,  mechanically.  Misled  by  this  point,  it 
has  been  common  to  reduce  the  weight  and  size  of  bearings 
accordingly,  the  mistake  being  evident,  however,  when  it  is 
remembered  that  the  stoppage  of  circulating  water  in  the  cooler 
at  once  raises  the  load  on  the  low  pressure  piston;  while  a  broken 
or  damaged  outlet  valve  on  the  high  pressure  cylinder  may 
at  any  moment  throw  the  same  load  on  ail  parts  as  with  a  single 
cyHnder  machine. 

The  more  equable  distribution  of  the  load  throughout  the 
stroke  in  compound  compression,  just  noted,  also  aids  in  secur- 
ing a  higher  economy  in  steam  consumption  at  the  other  end 
of  the  machine;  for  it  makes  possible  an  earlier  cut-off  in  the 
steam  cylinder  and  a  consequently  greater  steam  expansion, 
with  its  attendant  saving — late  cut-offs  not  being  so  necessary 
to  prevent  "  centering."  ]\Iulti-stage  compression  with  effective 
intercoolers  between  stages  also  permits  a  higher  piston  speed, 
in  itself  a  factor  in  steam  economy  by  reducing  the  leakage 
and  condensation  in  the  steam  end. 

The  air  remaining  in  the  clearance  space  between  piston  and 
head  at  the  end  of  the  stroke  must  be  expanded  on  the  return 
stroke  to  atmospheric  pressure  before  free  air  can  enter  through 
the  inlet  valves.  Evidently  the  higher  the  pressure  in  this  clear- 
ance space,  the  greater  this  expanded  volume  and  the  lower  the 
intake  efficiency  of  the  cylinder.     In  single  stage  compression 


244      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

clearance  pressure  in  each  cylinder  is  terminal  pressure  in  that 
cylinder.  But  this  terminal  pressure  in  the  intake  cylinder 
of  a  compound  is  low,  usually  not  over  25  pounds  when  the 
final  working  pressure  is  100  pounds.  The  volumetric  efficiency 
of  compound  compression  cylinders  is  higher  for  this  reason, 
the  clearance  in  the  low  pressure  cyHnder  only  being  in 
question. 

Another  condition  conducive  to  high  volumetric  efificiency 
resulting  from  compound  compression  is  the  fact  that  terminal 
pressures,  and  consequently  terminal  temperatures,  are  lower 
than  in  single-stage  cylinders.  The  cylinder  walls  and  more 
particularly  the  heads,  with  the  valves  and  ports  which  may 
be  in  them,  are  therefore  kept  much  cooler  and  the  entering  air 
is  not  so  much  heated  by  contact  with  these  parts.  A  third 
element  entering  into  the  question  of  capacity  is  the  reduced 
leakage  in  stage  compression  cyHnders,  through  valves  and  past 
piston  and  rods,  with  the  incidental  loss  of  power.  It  is  evi- 
dent that  the  higher  the  pressure  the  greater  the  liabihty  to 
leakage;  and  the  smaller  range  of  partly  balanced  pressures 
in  multi-stage  cylinders  reduces  this  loss. 

One  of  the  greatest  difficulties  hitherto  encountered  in 
air  power  transmission  has  been  the  freezing  of  the  moisture 
in  the  air,  either  in  the  pipe  line  or  at  the  exhaust  ports  of  the 
air  motors.  One  of  the  great  advantages  of  the  subdivision  of 
compression  into  several  stages  lies  in  the  opportunity  it  affords 
for  cooHng  the  compressed  air  at  intermediate  stages  to  a  tem- 
perature at  which  its  moisture  will  be  precipitated.  Of  course, 
practically  all  of  this  condensation  occurs  in  the  inter-  and 
aftercoolers;  and  herein  appears  the  necessity  for  a  design 
which  will  pass  the  air  at  low  velocity  with  full  opportunity  for 
cooling  on  the  water  tubes.  The  moisture  in  suspension  is 
withdrawn  through  the  drain  pipe.  It  is  needless  to  say  that 
unless  some  provision  is  made  for  arresting  and  withdrawing 
the  condensed  water  from  the  intercooler,  the  value  of  the  latter 
as  an  air  drier  is  lost;  for  the  moisture  is  carried  over  into  the 
compression  cyHnders,  producing  a  condition  of  cutting  and 
leakage  in  valves  and  rings,  and  finally  working  out  into  the 


APPENDIX   F  245 

pipe  line.  Aftercoolers  are  in  some  instances  as  important  as 
intercoolers  in  removing  moisture. 

If  air  be  compressed  in  a  single  cylinder  from  atmospheric 
pressure  and  temperature  of  60  degrees  Fahrenheit  to  a  final 
pressure  of  100  pounds,  the  maximum  temperature  attained 
may  be  484  degrees  Fahrenheit.  This  temperature  is  man- 
ifestly destructive  to  common  lubricants  and  oils  of  ordinary 
quality  are  burned  into  a  solid,  gritty,  coke-like  or  gummy 
substance  which  gives  the  very  reverse  of  proper  lubrication, 
unless  proper  jacketing  devices  are  employed  to  keep  the  parts 
cold.  This  deposit,  moreover,  collecting  in  ports  and  valves, 
may  so  obstruct  and  clog  them  as  to  cause  leakage  and  throw 
an  added  load  on  the  compressor.  If,  however,  this  same 
volume  of  air  be  compressed  in  the  first  cyhnder  to  a  pressure 
of  25  pounds,  the  highest  temperature  which  can  be  reached 
is  only  22^2,  degrees,  a  heat  which  will  not  leave  a  deposit  or 
destroy  the  lubricating  qualities  of  good  oils  such  as  should  be 
used  in  compressor  work.  This  air,  passing  through  the  inter- 
cooler,  will  be  brought  back  to  about  the  original  temperature 
of  60  degrees  and  compressed  (in  a  2-stage  compressor)  from 
25  to  100  pounds  in  the  second  cylinder.  Here  the  maximum 
temperature  attained  will  be  but  little  (if  any)  in  excess  of  that 
in  the  first  cylinder,  since  the  heat  of  compression  is  a  function 
of  the  number  of  compressions  and  is  almost  wholly  independent 
of  the  initial  pressure.  In  multi-stage  compressors,  therefore, 
the  conditions  of  temperature  are  seen  to  be  most  conducive 
to  thorough  lubrication  of  pistons  and  valves,  tending  toward 
durability  and  tightness  of  working  parts,  with  long  Hfe  and  high 
efficiency  of  the  machine. 

The  advantages  of  compound  air  compression  have  gradually 
forced  themselves  upon  the  attention  of  pneumatic  engineers. 
Not  many  years  ago,  when  pressures  were  lower,  the  majority 
of  compressors  were  single-stage  machines.  But  with  the 
grownng  tendency  toward  higher  pressures,  and  an  under- 
standing of  needed  economies,  compound  compressors  came  into 
greater  prominence;  and  of  late  much  the  larger  percentage  of 
installations  have  been  machines  of  this  stvle. 


246  SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

But  it  will  not  do  to  reason  that  a  compound  compressor, 
simply  as  a  compound,  is  more  economical  than  a  high-class 
simple  machine,  for  such  is  not  the  case.  On  the  contrary, 
only  compounds  of  the  highest  class  are  advantageous  or  deserve 
any  consideration  from  an  economical  standpoint. 

The  gains  depend,  not  simply  upon  stage  compression  and 
effective  cooling,  but  also  upon  correct  design  throughout  the 
machine  and  a  consistent  attention  to  every  detail. 

Every  condition  which  may  possibly  affect  the  air  from 
intake  to  discharge  must  be  properly  considered  and  provided 
for.  Some  of  these  defects  which  may  offset  compression 
economy  have  been  noted  from  time  to  time  throughout  the 
preceding  discussion.  But  their  importance  merits  a  repetition 
here;  a  weak  structure  and  small  bearings  (based  on  a  mistaken 
idea  of  reduced  stresses)  with  no  provision  for  unexpected  con- 
tingencies, resulting  in  excessive  friction  losses;  multiplicity 
of  wearing  parts,  absorbing  a  large  portion  of  the  power  theoret- 
ically saved;  heated  and  restricted  air  passages,  inefficient 
valves,  neglect  of  proper  jacket  and  head  cooling;  frugal  and 
ineffective  intercoolers;  poor  workmanship,  resulting  in  leakage 
losses.  Not  only  may  these  defects  largely  offset  the  saving 
by  compression  in  stages,  but  it  is  a  fact  that  compounds  new 
on  the  market  may  require  more  power  per  cubic  foot  of  air 
compressed  than  well-designed,  high-class,  simple  compressors 
of  equivalent  capacity. 

The  term  "  compound  "  or  "  2-stage  "  as  applied  to  air 
compressors  should  properly  stand  for  superior  economy.  The 
buyer  of  a  compound  rightfully  expects  a  saving  by  its  use. 
But  poor  practice  may  prove  the  undoing  of  the  best  theory. 
That  compressor  only  is  a  commercial  and  economical  success 
which  embodies  a  sound  theory  in  a  mechanical  structure  cor- 
rectly designed,  built  by  skilled  and  careful  workmen,  and  so 
simple  as  to  be  readily  understood,  handled  and  maintained 
by  mechanics  of  average  intelligence. — Lucius  I.  Wightman,  in 
'^ Power,'"  January,  igo6. 

Altitude  Compression.  The  height  of  the  atmosphere 
surrounding  the  earth  has  been  variously  estimated  to  extend 


APPENDIX  F  247 

from  50  to  20,000  miles,  and  since  air  has  weight  it  exerts 
upon  surrounding  objects  a  pressure  of  the  air  column  above 
the  object. 

Being  very  elastic  its  weight  will  cause  it  to  have  a  variable 
density  throughout  its  height  and  exert  varying  pressures  at 
different  altitudes.  At  the  sea  level  an  atmospheric  column 
balances  a  column  of  mercury  30  inches  high  and  of  equal  area, 
which  corresponds  to  a  pressure  of  14.7  pounds  per  square  inch. 
The  variation  in  pressure  for  different  elevations  has  been 
determined  by  barometric  observations  and  is  given  in  the 
table  following,  from  which  it  will  be  noted  that  the  atmos- 
pheric pressure  decreases  with  increasing  height,  and  as  a 
consequence  one  pound  of  air  occupies  a  greater  volume  at 
an  altitude  than  at  the  sea  level  (at  the  same  temperature); 
or  a  cubic  foot  of  air  weighs  less  at  a  higher  altitude  than  at  a 
lower  one. 

In  descending  the  shaft  of  a  mine  the  contrary  effect  is 
noticed,  but  in  a  mine  or  any  level  below  the  sea  increase  in 
density  is  counterbalanced  by  increase  in  temperature  as  we 
approach  the  center  of  the  earth.  The  temperature  of  the 
atmosphere  also  changes  with  increasing  altitude,  but  is 
not  always  uniform  for  any  two  places  at  the  same  eleva- 
tion. 

The  volumetric  efficiency  of  an  air  compressor,  expressed 
in  terms  of  free  air,  is  the  same  at  all  altitudes  (for  the  displace- 
ment in  a  given  size  of  cyhnder  is  the  same) ;  but  the  volumetric 
efficiency,  expressed  in  terms  of  compressed  air  at  a  given  pres- 
sure, decreases  as  the  altitude  increases;  for  the  quantity  of 
air  taken  into  a  given  cylinder  per  stroke  being  less  dense  at  an 
altitude  (due  to  lower  initial  or  atmospheric  pressure)  it  will 
be  compressed  into  a  smaller  space  for  a  given  terminal  pressure. 

To  cite  an  example : 

300  cubic  feet  of  air,  at  atmospheric  pressure  of  14.7  pounds, 
compressed  to  80  pounds    gage,  will    represent  a  volume  of 

•^00  X — ^  =  46.1;  cubic  feet. 
•^        94.7 

If  the  atmospheric  pressure  was  10.10  pounds  in  the  above 


248      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

lO.IO 

example,  then  the  volume  delivered  would  be  300  X =  33-50 

^  ^         90.10 

cubic  feet;  or  the  volumetric  efficiency  of  a  compressor  per- 
forming the  above  work  at  an  altitude  of  10,000  feet  would  be 
but  72  per  cent  of  what  it  would  be  at  the  sea  level. 

In  order,  therefore,  that  an  air  compressor  may  dehver 
at  an  altitude  a  volume  of  compressed  air  per  stroke  equal  to 
that  which  it  would  deliver  at  sea  level,  the  intake  cyHnder  of 
the  altitude  compressor  must  be  proportionately  larger  than 
that  of  the  compressor  at  sea  level. 

Less  power  is  required  at  an  altitude  than  at  sea  level  to 
compress  the  free  air,  taken  in  by  a  compressor  of  a  given  size, 
to  the  same  terminal  pressure  (as  shown  in  table  following); 
but  in  order  to  compress  a  quantity  of  air  at  an  altitude  which 
is  to  be  equivalent  in  efifect  to  air  at  sea  level,  more  power  is 
required,  because  the  reduction  in  power  is  not  proportionate 
to  the  increase  in  volume  necessary. 

Example : 

To  compress  100  cubic  feet  of  free  air,  at  atmospheric  pres- 
sure of  14.7  pounds,  to  80  pounds  gage,  requires  17.75  indicated 
horse-power. 

To  compress  100  cubic  feet  of  free  air,  at  atmospheric  pressure 
of  10.10  pounds,  to  80  pounds  gage,  requires  15.25  indicated 
horse-power. 

But  the  equivalent  volume  of  100  cubic  feet  of  free  air  at 

100 
an  atmospheric  pressure  of  14.7  pounds  is  —  =  139  cubic  feet 

.72 

at  an  atmospheric  pressure  of  10.10  pounds;  and  139X.1525  = 

21.2   indicated  horse-power;    or   (for   the   conditions   assumed 

here)  3.45  indicated  horse-power  more  are  required  at  10,000 

feet  altitude  to  produce  the  same  effect  as  at  sea  level. 

The  net  efficiency  of  a  compressed  air  plant  depends  upon 
the  type  of  compressor  and  engine  or  motor  using  the  air.  the 
working  pressure  and  initial  temperature,  and  whether  the  air 
is  used  expansively  or  at  full  stroke. 

Most  compressed  air  engines  or  motors  (such  as  rock  drills, 
pumps  and  hoists),  working  at  an  altitude,  use  the  air  at  full 


APPENDIX  F 


249 


stroke;  in  the  following  table  the  volumetric  efficiencies,  at 
different  altitudes,  of  an  air  compressor  supplying  such  engines 
with  air  at  full  stroke  are  given. 


RELATIVE  VOLUMETRIC  EFFICIENCIES  AND  DIFFERENCES  IN 
WORK  DONE  IN  COMPRESSING  AIR  AT  DIFFERENT  ELEVATIONS 
COMPARED   WITH   CONDITIONS   AT   SEA   LEVEL 


■    u.   1     1 

U 

+^'7* 

^ 

Atmospheric 

c  ^ 

_y  BJi    --SP 

c  g   ■   m 

•^  .-  t:  « 

0) 

> 

V 

Pressure. 

Feet)  of 
(at  60°  F. 
;ponding 
mosphere. 

rt  0^ 
0      0 

Volumetri 
n    Air    Co 
ing  Air  unc 
80  Pounds 
Level  Con 
ture  60°  F 

Decrease  i 
r  Compress 
pacity,  Dc 
80  Pound 
jre. 

Extra  Woi 
^"ompress  r 
r  EquivaU 
at  Sea  Le' 
5  Pressure. 

rt 
o 

3 

2 

a! 
3 

r^ 

M    . 

0 1. 
■0^5 

Percentage  of 
Efficiency   of    a 
pressfjr  Dcliveri 
a  Pressure  of    '. 
referred  to  Sea 
tions  (Tempera 

0  o^<:  c 

(Cu 
of  A 

T  Co 

re  of 

<1>    Ql     (-• 

1^1 

itage 
n  an 
iven 
g  Ail 
Pr 

tage 
red  t 
y  of 
t  to  . 
Pou 

•a 

3 

< 

0 
C 

c 

3 

0 

Volume 
Pound 

unde 
Prcssu 

cj  0 

Percen 

Power  i 

of  a  G 

liverin 

Percen 

Requi 

Quantit 

in  Effec 

to  80 

o 

30.00 

14.7 

13-14 

100. 0 

0.0 

0.0 

500 

29-45 

14-45 

13 

36 

1-7 

98.5 

0.38 

I-S 

1000 

28.90 

14.12 

13 

66 

4.0 

96.5 

1.38 

2-5 

1500 

28.35 

13.92 

13 

85 

5-4 

95  0 

2.05 

3-0 

2000 

27.78 

13.61 

14 

19 

8.0 

93-5 

2-45 

4.2 

3000 

26.75 

13.10 

14 

72 

12.0 

90.5 

4.02 

6.1 

4000 

25-75 

12.61 

15 

31 

16.5 

87-5 

5-27 

8.5 

5000 

24-78 

12.15 

15 

88 

20.8 

84-7 

7.04 

10. 0 

6000 

23-86 

11-75 

16 

41 

24.9 

82.0 

8.41 

II .  2 

7000 

22.97 

11.27 

17 

15 

30.6 

79-5 

9.70 

14.0 

8000 

22. 10 

10.8s 

17 

78 

35-4 

77.0 

11.05 

15-5 

gooo 

21.30 

10.45 

18 

50 

41 .0 

74-5 

12.80 

173 

10  000 

20.60 

10. 10 

19 

10 

45  5 

72.2 

14.00 

19-5 

In  designing  an  air  compressor  for  a  high  altitude,  the  above 
factors  have  to  be  taken  into  account;  in  addition  to  these 
the  influence  of  a  lower  back  pressure  in  the  steam  cylinder 
will  have  to  be  considered  in  the  proportion  of  cylinders.  Again, 
a  compound  air  compressor  designed  for  an  altitude  must  have 
a  higher  ratio  of  cylinder  diameters,  so  as  to  divide  the  work 
equally. 

Conditions  of  Air  Cylinder  Lubrication.  The  fires  which 
sometimes  occur  in  air  compressor  cylinders  are  due  to  the 
lubricating  oil,  the  only  combustible  present.  Inferior  oils 
cause  explosions  by  reason  of  the  large  amount  of  carbon  and 


250      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

foreign  substances  they  contain,  but  they  are  not  the  only 
oils  responsible  for  these  explosions.  The  conditions  pecuhar 
to  a  given  machine  may  facilitate  or  retard  combustion.  For 
instance,  in  a  chemical  works,  a  copper  or  coal  mine,  foreign 
substances  in  the  atmosphere  may  furnish  something  to  feed  the 
fire  caused  by  combustion  of  the  residual  carbon.  Most  oxida- 
tion in  all  cases  takes  place  at  the  junction  between  cylinder 
and  discharge  pipe.  Continual  oxidation  so  reduces  the  size 
of  the  pipe  that  more  air  is  compressed  in  the  cylinder  than  can 
pass  through  the  pipe.  Increased  friction  and  compression 
cause  an  abnormal  degree  of  heat  in  the  cylinder,  and  trouble 
from  fire  is  experienced.  In  all  cases  an  oil  should  be  used  which 
causes  the  least  oxidation  possible,  its  flash-point  being  as  high 
as  consistent  with  good  lubricating  qualities.  Ignition  in  the 
compressed  air  delivery  pipe  is  not  uncommon,  as  shown  by  the 
explosion  of  two  air  receivers  during  the  construction  of  the 
New  York  aqueduct ;  in  one  case  the  engine-room  was  destroyed 
by  the  resultant  fire.  The  explosion  was  caused  by  the  use  of 
an  oil  of  very  low  flash-point.  This  ignition  has  extended  in 
some  cases  to  the  air  receiver,  and  in  one  instance  the  flames 
were  carried  down  into  the  mine  by  the  compressed  air.  In 
some  cases  the  pressure  recorded  by  the  gage  has  not  been  so 
high  as  that  equivalent  to  the  flash-point  temperature  of  the  oil. 
There  must,  however,  have  been  an  increase  in  temperature, 
and  this  is  due  to  a  momentary  increase  caused  by  the  con- 
stricted air  passages  being  choked  by  the  deposited  carbon. 
Trouble  is  increased  by  using  too  much  oil,  either  of  good  or 
bad  quality.  This  source  of  trouble  is  rather  common,  for 
many  engineers  have  an  idea  that  an  air  cyhnder  requires  as 
much  oil  as  a  steam  cyhnder.  Consequently  deposition  of 
carbon  goes  on  at  a  very  rapid  rate.  The  carbon  deposit  can 
be  removed  by  kerosene.  Care  should,  however,  be  exercised 
in  the  use  of  that  same,  for  its  flash-point  is  about  120  degrees 
Fahrenheit,  and  its  careless  introduction  through  the  inlet  valve 
has  accounted  for  many  explosions.  Engineering  Times, 
London. 


APPENDIX   G 

SOME  AIR  LIFT   DATA 

Air  lifts  are  used  to  quite  an  extent  in  this  section  (Los 
Angeles,  Cal.)  for  raising  water  and  oil,  in  some  cases  oper- 
ating in  oil  wells  2000  feet  deep  or  more.  In  many  cases  the 
cost  of  installation  is  moderate,  and  in  all  cases  the  cost  of 
maintenance  is  very  low;  and  air  lifts,  with  compressors  of  any 
reasonable  size,  can  be  operated  more  economically  than  ordinary 
deep-well  pumps.  There  are  many  situations  where  they  are 
really  the  most  economical  appliances  that  can  be  used. 

It  is  necessary,  however,  to  have  a  proper  amount  of  sub- 
mergence to  get  economical  operation.  The  exact  amount 
of  submergence  for  best  work  varies  a  little  with  the  lift  and 
quantity  of  water  handled.  Ordinarily,  for  lifts  of  40  feet  or 
less  I  would  recommend  about  two  and  one-half  to  one — that  is, 
two  and  one-half  times  the  amount  of  pipe  below  the  surface  of 
the  water  in  the  well  when  pumping  the  maximum  quantity, 
to  the  lift  above  this  level.  With  lifts  of  from  50  to  80  feet, 
two  to  one  generally  gives  good  results.  On  deeper  lifts  one 
and  one-half  to  one  is  frequently  used.  There  are  situations 
where  sufficient  submergence  cannot  possibly  be  obtained, 
and  while  the  pumps  may  be  operated  with  considerably  less 
submergence,  it  generally  increases  the  cost  of  pumping  some- 
what. 

The  quantity  of  air  required  depends  somewhat  on  the  size 
of  the  installation,  the  proper  proportioning  of  the  pipes,  flow 
of  water  in  the  wells,  etc.,  and  it  is  impossible  to  give  the  exact 
quantity,  as  it  is  very  seldom  that  two  wells  will  work  exactly 
aHke. 

I  give  herewith  a  table  showing  the  approximate  quantity 
of  air  required  and  working  pressure  for  all  ordinary  cases,  but 

251 


252 


SUBWAYS  AND   TUNNELS   OF  NEW  YORK 


know  of  a  number  of  installations  that  are  operated  successfully 
with  from  15  to  20  per  cent  less  air  than  is  shown  in  this  table, 
and  a  few  installations  that  use  more. 

APPROXIMATE  CUBIC  FEET  OF  FREE  AIR  AND  WORKING  PRESSURE 
REQUIRED  TO  RAISE  ONE  GALLON  OF  WATER  BY  AN  AIR  LIFT. 


RATIO   OF   SUBMERGENCE    TO    LIFT. 


I  to  I. 

I  J  to  I. 

2  to  I. 

2|  to  I. 

Lift  in 
Feet. 

Free  Air, 
Cubic 
Feet. 

Working 
Press- 
ure, 
Pounds. 

Free  Air, 
Cubic 
Feet. 

Working 
Press- 
ure, 
Pounds. 

Free  Air, 
Cubic 
Feet. 

Working 
Press- 
ure, 
Pounds. 

Free  Air, 
Cubic 
Feet. 

Working 
Press- 
ure, 
Pounds. 

20 

30 

40 

50 

60 

80 

100 

120 

140 

160 

180 

200 

0.428 

0.47 

0.508 

0.546 

0.582 

0.653 
0.72 

0.785 
0.847 
0.907 
0.965 
1.022 

9 

i3i 
18 

22j 

27 

36 

45 
54 
63 
72 
81 
90 

0.31 

0.35 

0.387 

0.422 

0.457 
0.522 

0.585 
0.642 
0.697 

0.755 

0.81 

0.862 

13* 
20 

27 

34 

40^ 

54 

67I 

81 

942 
108 
1212 
135 

0.252 
0.  29 

0.325 

0.36 

0.392 

0.455 
0.512 
0.567 
0.622 
0.675 
0.725 
0.775 

18 

27 

36 

45 

54 

72 

90 

108 

126 

144 

162 

180 

0.217 

0.255 
0.287 
0.32 

0.35 

0.41 

0.465 

0.52 

0.572 

0.624 

0.672 

0.72 

22i 

34 

45 

56 

67i 

90 

II2j 

13s 

157* 

180 

202 

225 

In  selecting  a  compressor  it  is  well  to  allow  a  surplus  over 
the  amount  given  in  the  table,  as  it  cannot  always  be  known 
before  testing  how  much  the  water  in  the  wells  will  fall  when 
being  pumped;  and  while  some  of  the  better  makes  of  the 
larger  sizes  of  compressors  will  give  a  volumetric  efficiency  of 
over  90  per  cent,  there  are  some  of  the  smaller  sizes  of  com- 
pressors, with  poppet  inlet  valves,  that  are  deficient  in  inlet 
valve  area,  and  some  of  them  will  not  deliver  60  per  cent  of  the 
amount  of  air  that  is  shown  by  piston  displacement  when  running 
at  full  speed.  This,  of  course,  varies  with  the  inlet  valve  area 
and  speed. 

The  size  of  air  pipe  is  not  very  important,  providing  it 
is  large  enough  to  carry  the  air  without  undue  friction,  and  the 
working  pressure  given  is  based  on  there  being  very  little  fric- 
tion. 


APPENDIX  G  253 

The  size  of  the  pipe  in  which  the  water  is  Hfted  to  the  sur- 
face is,  however,  quite  important,  as  there  must  be  a  fairly 
high  velocity  to  work  properly,  and  it  is  better  to  err  in  having 
the  pipe  a  little  too  small  than  too  large.  The  best  work  is 
generally  obtained  with  a  flow  of  from  12  to  18  gallons  per 
square  inch  of  section.  Smaller  pipes  will  not  stand  quite 
so  high  a  velocity  as  larger  sizes. 

The  arrangement  of  the  air  nozzles  at  the  bottom  is  not 
a  matter  of  very  great  importance,  provided,  of  course,  the  air 
pipe  is  somewhat  above  the  bottom  of  the  water  pipe.  There 
are  a  number  of  different  arrangements  that  give  good  results. 

In  some  cases,  where  it  is  desired  to  deliver  the  w^ater  at 
some  distance  away  from  and  above  the  well,  where  sufficient 
submergence  cannot  be  obtained,  air  displacement  pumps  are 
used;  that  is,  a  cylinder  or  chamber  is  lowered  into  the  well 
below  the  water  line  and  provided  with  valves  somewhat  similar 
to  pump  cyHnders,  being  alternately  filled  and  emptied  with 
air  under  pressure.  What  is  known  as  the  "  dense  air  "  system, 
by  which  the  air  is  returned  to  the  compressor  under  consider- 
able pressure,  increases  the  economy  of  the  compressor  and 
makes  a  satisfactory  and  very  economically  operated  pumping 
plant. 

Direct-acting  deep-well  steam  pumps  are  generally  very 
wasteful  in  the  use  of  steam,  and  very  seldom  are  any  more 
economical  to  operate  than  a  good  air-lift  system,  properly 
installed.  All  kinds  of  deep-well  pumps,  having  a  long  line  of 
rods,  generally  are  quite  expensive  to  maintain,  to  say  nothing 
of  the  trouble  and  time  lost  in  pulling  and  replacing  rods  and 
buckets.  They  are  good  things  to  keep  away  from  wherever 
it  is  possible,  particularly  where  any  considerable  quantity  of 
water  is  required  from  deep  wells.  However,  when  operated 
at  very  slow  speeds,  and  large  capacity  is  not  required,  their 
use  is  sometimes  admissible.     Power,  New  York. 

Cost  of  Pumping  with  the  Air  Lift.  This  question  is  usually 
asked  without  giving  several  items  which  largely  determine 
the  answer.  Thus,  coal  at  $2.00  is  one  thing,  at  $4.00,  another. 
Again,  some  wells  are  nearby,  and  in  other  plants  the  pipe  invest- 


254  SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

ment  is  greater  because  of  scattered  wells.  Speaking  gen- 
erally, the  average  cost  per  thousand  gallons  pumped  depends 
on  the  size  of  plant  and  height  of  lift.  In  a  4,000,000  gallon 
plant,  with  a  50-foot  lift,  it  is  about  one-third  cent  per  1000 
gallons.  In  a  larger  plant,  with  a  35-foot  Hft,  with  coal  at 
$2.00,  it  is  about  one  and  one-half  mills.  In  another  case, 
where  the  lift  is  75  feet  and  the  capacity  one  and  one-third 
million  gallons,  the  cost  is  one  cent  per  1000  gallons,  coal  cost- 
ing $2.00.  In  a  plant  pumping  3,000,000  gallons  75  feet  high, 
the  cost  is  4.5  cents,  and  where  the  lift  is  50  feet,  3.5  cents. 
In  Pennsylvania,  a  plant  giving  175  gallons  per  minute  at  75- 
foot  lift,  costs  one  and  one-third  cents  per  1000  gallons.  In  a 
proposed  municipal  plant,  100,000,000  gallons  per  twenty- 
four  hours,  50-foot  lift,  and  with  coal  at  Si. 50  a  ton,  the  cost 
figured  i  mill  per  1000  gallons,  including  all  fixed  and  operating 
expenses.  In  another  case,  involving  the  handling  of  about 
15,000,000  gallons  of  water  30  feet  high  every  twenty-four 
hours,  using  compound  condensing  compressors  and  with 
coal  at  $2.00  per  ton,  other  figures  being  estimated  on  a  very 
generous  basis,  the  cost  nets  about  $2.50  per  1,000,000  gallons, 
or  about  two  and  one-half  mills  per  1000  gallons.  These  figures 
cover  fuel,  oil,  labor,  sinking  fund,  interest  and  taxes. 

In  many  cases  the  introduction  of  the  air  lift  may  be  effected 
at  little  expense,  often  involving  the  purchase  only  of  an  air 
compressor,  a  receiver  and  a  small  amount  of  pipe;  but  the 
following  is  estimated  on  a  basis  which  will  cover  the  greatest 
amount  of  expense  likely  to  be  incurred,  with  a  view  of  showing 
particularly  that  the  interest  and  depreciation  charges  under 
the  most  extreme  conditions  are  not  likely  to  develop  into 
formidable  figures.  The  following  is  a  list  of  the  complete 
equipment  for  an  air  lift  plant  to  raise  1,500,000  gallons  per 
twenty  hours,  or  1250  gallons  per  minute.  Total  hft,  75  feet; 
air  compressor,  complete,  ready  for  foundation  and  piping; 
air  receiver;  boiler,  85  h.p.,  with  feed  pumps,  etc.,  bricked  up 
and  ready  for  use,  including  building  and  value  of  ground  so 
occupied;  tank,  19,000  gallons  capacity,  including  suitable 
timber  framework  to  bring  tank  75  feet  above  water  level;   two 


APPENDIX  G  255 

1 2-inch  wells,  each  135  feet  deep,  cased;  casing,  450  feet  yf-inch 
light  pipe;  air  pipe,  500  feet  of  3-inch  air  pipe  in  wells;  air 
pipe,  1000  feet  of  4-inch  air  line  from  receiver  to  wells;  water 
pipe,  1250  feet  of  12,  10  and  8-inch  cast-iron  distributing  main, 
leaded  joints,  from  tank  to  works,  laid  below  frost  (air  line 
laid  in  same  trench);  all  other  pipe  and  fittings;  compressor, 
receiver  and  tank  foundations,  laid  in  cement;  special  automatic 
governing  mechanism;  total  estimated  cost  of  complete  plant, 
ready  to  run,  as  above,  $8750.  This  is  intended  to  include 
everything  which  may  be  considered  as  a  legitimate  expense  in 
this  connection.  In  many  cases  the  buildings,  boilers,  tanks, 
wells,  pipe  lines,  ground  space,  and  other  items  do  not  represent 
a  present  expense,  being  already  on  the  ground. 

We  may  estimate  the  cost  of  operation  as  follows:  Engineer, 
double  shift,  at  $2.25  per  day,  $4.50,  one-fifth  time  chargeable 
to  pumping  plant,  per  day,  $0.90;  fireman,  double  shift,  at 
$1.75  per  day,  $3.50,  on  the  basis  of  one  man  required  for  each 
250  h.p.  of  boiler,  for  85  h.p.  per  day,  $1.19;  fuel,  85  h.p., 
twenty  hours,  say  four  and  one-quarter  tons,  at  $2.00  per  ton, 
per  day,  $8.50;  oil,  waste  and  sundries,  say,  60  cents;  interest 
on  investment  of  $8750  at  5  per  cent,  figuring  eleven  25- 
day  months,  or  275  working  days  per  year,  per  day,  $1.91; 
deterioration,  covering  sinking  fund,  repairs,  etc.,  providing 
for  renewal  of  complete  plant  every  ten  years,  same  basis  as 
interest  but  10  per  cent,  per  day,  $3.18;  insurance  and  taxes 
at  I  per  cent,  as  above,  per  day,  thirty-two  cents;  total  estimated 
cost  of  pumping  1,500,000  gallons  per  day,  75  feet  high,  under 
the  above  conditions,  $16.60.  Cost  of  each  1000  gallons 
$i6.6oH-i5oo  =  $o.oiio7.     Engineering  Record. 


APPENDIX   H 

COMPRESSED   AIR   LOCOMOTIVES 

Two  Compressed  Air  Mine  Locomotives.  The  halftones  here- 
with show  two  interesting  compressed  air  locomotives  recently 
built  for  mine  service  by  the  Baldwin  Locomotive  Works.  Both 
these  engines  are  of  the  four-coupled  t}pe,  but  they  differ  from 
each  other  more  than  the  half  tones  suggest,  both  in  size  and  in 
many  constructive  details. 

The  locomotive  for  the  Lehigh  Valley  Coal  Company  is 
built  within  a  width  limit  of  5  feet  6  inches  and  a  height  limit  of 
5  feet  7  inches,  the  length  over  the  bumpers  being  14  feet.  The 
frames  are  of  forged  iron,  and  they  have  a  slab  section  ahead 
of  the  leading  driving  pedestals.  This  construction  provides 
a  ready  means  for  supporting  the  cylinders,  which  are  placed 
between  the  frames  and  are  securely  bolted  to  them.  The 
cylinders  are  set  on  an  incline  of  one  in  ten,  so  that  the  main 
rods  will  clear  the  leading  axle.  The  driving  axle,  of  course, 
has  two  cranks  inside  and  is  a  steel  forging  made  in  a  single 
piece.  There  are  two  similar  air  tanks  with  a  combined  capacity 
of  95  cubic  feet.  Air  is  stored  in  these  tanks  at  an  initial  pres- 
cure  of  800  pounds,  and  a  reducer  keeps  an  auxiliary  reservoir 
constantly  charged  to  a  working  pressure  of  140  pounds.  Safety 
valves  are  provided  for  both  the  main  and  the  auxiliary  reservoirs 
at  their  respective  pressures.  The  equipment  includes  air 
brakes  for  all  the  wheels,  also  four  sand-boxes  with  spouts  to 
all  the  wheels.     The  principal  dimensions  are  as  follows: 

Gage,  4  feet. 

Cylinder,  8  by  12  inches. 
Driving-wheels,  28  inches  diameter. 
Wheel-base,  4  feet. 

256 


APPENDIX  H 


257 


Tractive  force,  3260  pounds. 
Weight,  18,000  pounds. 

The  locomotive  for  the  Gilson  Asphaltum  Company,  Mack, 
Col.,  may  be  said   to  be  about  one-half   the  size  or  capacity 


of  the  preceding.  It  is  lighter  and  more  compact.  In  the 
mine  where  this  locomotive  is  used  the  air  is  charged  with 
gilsonite  or  asphalt  dust,  rendering  it  dangerously  explosive, 
so  that  compressed  air  haulage  was  adopted  as  a  safety  pre- 
caution independently  of  other  considerations.     The  narrow- 


258 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


ness  of  the  gage  permitted  only  a  single  air  storage  tank  which 
has  a  capacity  of  39  cubic  feet.  The  charging  pressure  is 
800  pounds  and  the  working  pressure  of  the  auxiliary  tank 
140  pounds.     The  frames  are  of  plate  steel,  supported  on  coiled 


springs.  The  air  tank  rests  directly  on  the  frames,  the  points 
of  support  being  over  the  springs.  The  cylinders  are  placed 
outside  the  frames  in  a  horizontal  position.  The  function  of 
the  heat  radiating  rings  cast  around  the  cylinders  is  in  this  case 
reversed,  as  the  cylinders  cool  in  working  and  the  rings  absorb 


APPENDIX   H 


259 


heat  from  the  atmosphere  and  help  maintain  the  temperature 
at  a  workable  point  within. 

This  engine  is  provided  with  a  sand-box  on  each  side,  and 
sand  can  be  blown  under  either  front  or  back  v;heels.  Air- 
brake equipment  also  is  provided  with  shoes  on  all  the  wheels. 
The  auxiliary  air  tank  is  placed  on  the  left  side  and  is  fitted  with 
a  safety  valve,  as  is  also  the  main  tank.  The  nozzle  and  valve 
for  recharging  are  seen  on  the  side.  The  principal  dimensions 
of  this  engine  are  as  follows: 

Gage,  2  feet  6  inches. 
Cylinders,  5I  by  10  inches. 
Driving-wheels,  20  inches  diameter. 
Wheel  base,  3  feet  6  inches. 
Weight,  8650  pounds. 
Tractive  force,  1800  pounds. 

From  Compressed  Air  Magazine. 

German  Compressed  Air  Mine  Locomotives.  We  illustrate 
on  these  pages  a  type  of  compressed  air  locomotive  introduced 
by  the  Berhner  ]Maschinenbau- 
Actiengesellschaft,  Figs,  i  and 
2  being  end  and  side  outline  ele- 
vations respectively,  not  to  the 
same  scale,  and  the  half  tone, 
Fig.  3,  showing  a  locomotive  in 
actual  service  and  stopped  at 
a  charging  station  for  a  fresh 
supply  of  air. 

The  standard  pattern  of  the 
machine  is  of  8  to  12  nominal 
horse-power,  but  is  capable  of 
working  up  to  24  h.p.  as  a  maxi- 
mum, and,  under  ordinary  condi- 
tions of  gradient,  will  haul  about 
forty  full  tubs,  each  with  a  net 
load  of  II  cwts.,  at  a  speed  of 
five  and  one-half  miles  per  hour. 


Fig.  1. 


It  will  run  a  distance  of  about 


260 


SUBWAYS  AND  TUNXELS   OF  NEW  YORK 


1600  to  3200  yards  with  a  single  charge  of  air,  the  pressure 
sinking  from  about  750  pounds  per  square  inch  to  150  pounds. 


Fig.  2. 


Even  under  the  latter  conditions,  however,  the  engine  can  run 
empty  for  another  1500  to  2000  yards,  so  that  the  driver  can 


Fig.  3. 


easily   reach   a   recharging   station    should   the    locomotive   be 
unable  to  haul  the  train  at  any  point  of  its  course. 


APPKNDIX   TI  261 

The  dimensions  of  the  locomotive  are  as  follows:  Total 
length  over  buffers,  13  feet;  maximum  height  above  the  rails, 
5  feet;  maximum  width,  3  feet;  wheel-base,  40  inches.  With 
these  dimensions  curves  of  7,t,  feet  radius  can  be  negotiated 
without  difficulty.  The  effective  adhesion  weight  of  the  loco- 
motive is  about  five  and  one-half  tons,  so  that  it  is  capable  of 
exerting  considerable  tractive  force,  even  on  greasy  rails,  without 
slipping. 

As  shown  in  Figs,  i  and  2,  the  locomotive  consists  of  the 
main  air  receiver,  a,  auxiliary  receiver,  b,  the  motion,  c,  and  the 
frame,  d,  with  the  requisite  valves  and  fittings,  including  safety 
valves  and  pressure  gages  for  both  air  vessels,  a  reducing 
valve,  signal  bell,  sanding  appliances,  powerful  brake,  lamp, 
etc.  The  driver's  seat  is  above  the  driving  cylinders,  and 
all  parts  of  the  motion  are  easy  of  access.  The  air  supply  is 
compressed  to  11 25  or  1500  pounds  per  square  inch,  and  stored 
in  reservoirs.  These  are  connected  by  air  mains  with  charging 
reservoirs  (Fig.  3),  situated  at  a  convenient  place  for  recharging. 
This  latter  operation  is  effected  in  a  very  short  time;  in  fact, 
it  is  claimed  that  one  to  one  and  one-half  minutes  will  be  suf- 
ficient, on  account  of  the  high  pressure  in  the  recharging  cylin- 
ders. The  difference  between  the  pressure  of  750  pounds  in  the 
locomotive  air  cylinder  and  1500  pounds  in  the  compressor 
equalizes  the  work  of  the  latter,  so  that  it  can  be  kept  running 
continuously,  even  when  the  loads  to  be  hauled  are  subjected 
to  considerable  fluctuation.  In  the  event  of  the  compressor 
supplying  more  air  than  is  being  consumed  by  the  locomotives, 
an  automatic  valve  on  the  former  opens  and  allows  the  com- 
pressor to  run  empty  until  the  pressure  in  the  reservoirs  has 
fallen  below  the  limit  of  1500  pounds. 

The  working  pressure  in  the  engine  cylinders  is  lowered  to 
150  pounds  by  a  reducing  valve  of  special  design,  the  air  being 
passed  through  an  auxiliary  air  chamber.  An  early  cut-off 
permits  the  expansive  power  of  the  air  to  be  fully  utilized. 

From  Compressed  Air  Magazine. 


APPENDIX   I 

ROCK   DRILLS   AND   MOUNTINGS 

The  percussive  rock  drill,  as  distinguished  from  all  other 
types,  is  an  American  invention,  the  first  practical  patents 
having  been  taken  out  by  J.  J.  Couch,  of  Philadelphia,  in  1849. 
Couch  was  assisted  in  building  this  drill  by  Joseph  W.  Fowle, 
later  of  Boston,  their  experiments  being  carried  on  during  the 
year  1848.     The  Couch  drill  was  a  crank-and-fiy -wheel  machine, 


jr^.-f'^ 


Rand  "  Little  Giant"  Tappet  Valve  Rock  Drill  with  Plain  Slide  Valve. 

and  its  application  to  practical  work  was  therefore  limited  to 
surface  hole  driUing. 

In  1848  Couch  and  Fowle  separated,  Fowle  fihng  a  caveat 
in  1849.  This  caveat  describes  the  type  of  successful  power 
rock  drill  used  to-day.  The  chief  point  was  that  Fowle  first 
showed  a  drill  where  the  cutting  tool  is  attached  directly  to  the 
piston  or  to  the  cross-head  connected  with  the  piston.  This 
important  invention  was  described  by  William  Fowle,  in  his 
testimony  before  the  Massachusetts  Legislative  Committee  in 
the  contest  with  Burleigh  in  1874,  as  follows: 

"  My  first  idea  of  ever  driving  a  rock  drill  by  direct  action 
came  about  in  this  way:    I  was  sitting  in  my  office  one  day, 

262 


ATPENDIX    1 


263 


after  my  business  had  failed,  and  happening  to  take  up  an  old 
steam  cyUnder,  I  unconsciously  put  it  in  my  mouth  and  blew 
the  rod  in  and  out,  using  it  to  drive  in  some  tacks  with  which 
a  few  circulars  were  fastened  to  the  walls." 

The  nearest  approach  to  rock  drill  inventions  abroad  was 
in  the  German  work  of  Schumann  in  1854.  Fowle  being  without 
means,  but  a  genius  in  the  true  sense,  his  inventions  remained 
in  obscurity  until  Charles  Burleigh  purchased  his  patents  and 
produced  the  Burleigh  drill,  about  the  year  1866.  This  drill 
was  used  in  the  Hoosac  Tunnel  in  1867. 

Following  these  inventions  came  Haupt,  De  Volson  Wood, 
and  Simon  Ingersoll,  and  after  these  men  Sergeant,  Waring  and 


Rand  "Little  Giant"  Tappet  Valve  Rock  Drill  with  Balanced  Valve. 


Githens,  Githens  being  the  inventor  of  the  Rand  drill.  The 
Ingersoll  drill  was  invented  in  1871.* 

The  percussive  rock  drill  as  used  to-day  may  be  divided 
generally  into  three  types,  distinguished  by  the  operation  of 
the  valve. 

The  three  types  are:  where  the  valves  are  operated  by  tappets 
or  rockers,  by  steam  or  air,  or  a  combination  of  the  tappet  and 
air-thrown  system.  The  three  types  are  exemplified  by  the 
Rand,  the  Ingersoll,  and  the  Sergeant  drills,  respectively. 

The  valve  mechanism  of  the  Rand  drill  is  made  up  of  three 
pieces — the  valve,  the  rocker,  and  the  rocker  pin.  The  rocker, 
turning  on  the  rocker  pin,  is  in  contact  with  the  piston  at  one 

*  From  "  The  Historv  of  the  Rock  Drill,"  bv  \V.  L.  Saunders. 


264 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


point  and  projects  into  the  valve  in  its  upper  arm,  which  ends 
in  a  globular  form.  When  the  piston  moves,  a  curved  surface 
slides  under  a  rocker  contact,  pushing  the  rocker  upward  and 
swinging  the  valve  in  the  same  direction  as  the  piston  moves. 
On  the  reverse  travel  of  the  piston  this  series  of  movements  is 
exactly  reversed. 

The  distinguishing  characteristic  of  this  drill  is  the  positive 
character  of  its  valve  movement.  There  is  no  lost  motion, 
no  incomplete  travel,  no  fluttering  of  the  valve,  no  uncertainty 
in  the  machine  movement.  When  steam  or  air  is  admitted 
to  the  cylinder  the  piston  must  move;  and  when  the  piston 
moves,  the  valve  must  be  thrown. 


"  New  IngersoU  "  Air-thrown  Valve  Rock  Drill. 


While  the  tappet  movement  is  adapted  to  the  use  of  either 
steam  or  air,  it  is  as  a  steam-driven  machine  that  the  tappet 
drill  shows  its  pecuhar  superiority.  Steam  pressure  may  not 
be  high  and  the  steam  may  be  "  wet."  Under  such  conditions 
the  "  steam  thrown  "  valve  is  slow  in  action  and  labors  under 
the  burden  of  releasing  water  of  condensation.  The  tappet 
valve,  however,  is  superior  to  these  difficulties  encountered 
with  the  use  of  steam. 

The  IngersoU  drill  has  an  independent  air-thrown  valve, 
the  action  or  which  is  controlled  by  the  movement  of  the  piston. 
It  has  the  variable  stroke  so  necessary  in  working  in  caving, 
seamy  or  broken  ground;  while  its  quick  return  "  muds " 
the  hole  well.  The  blow  is  practically  uncushioned.  With 
compressed  air  or  with  reasonably  dry  steam  this  drill  will 
give  excellent  results  in  any  ordinary  material  to  which  per- 
cussion drills  are  suited. 


APPENDIX  I 


265 


In  certain  classes  of  work  there  are  several  positive  advan- 
tages in  the  "  tappet  "  principle  as  applied  to  rock  drill  valve 
movements.  But  the  mechanical  tappet,  struck  hundreds  of 
blows  per  minute  and  millions  of  blows  per  month  by  a  heavy 
piston  moving  at  high  velocity,  demands  qualities  of  design  and 
material  possible  of  attainment  only  to  a  long  experience.  Long 
practice  has  demonstrated  that  in  the  majority  of  cases  the  "  inde- 
pendent" valve  action  gives  a  better  machine,  using  less  air  or 
steam  per  foot  of  hole  drilled  than  any  other  pattern.  Yet  the 
positive  quality  of  the  tappet  movement  holds  an  important 
place  in  many  classes  of  work. 


"  Sergeant  "  Auxiliary  Valve  Rock  Drill. 

The  "  Sergeant  "  drill  is  a  successful  combination  of  the 
*'  independent  "  air-thrown  valve  of  spool  type  with  an  improved 
modification  of  the  tappet  action.  It  retains  certain  advantages, 
while  avoiding  defects,  of  both  valve  movements.  The  valve 
movement  is  one  in  which  the  strains,  shocks  and  jars  to  which 
the  tappet  or  rocker  is  subjected  are  transferred  from  the  main 
valve,  with  its  vital  and  delicate  functions,  to  a  smaller  aux- 
iliary valve  weighing  only  a  few  ounces,  specially  designed  to 
withstand  this  service  to  best  advantage,  and  cheaply  replaced 
when  worn.  But  the  wear  upon  it  is  almost  imperceptible. 
A  valve  seat  between  valve  chest  and  cylinder  carries  an  exten- 
sion fitting  into  a  recess  in  the  latter.  In  this  extension  is 
milled  an  arc-shaped  groove  or  slot  in  which  the  hght  aux- 
iliary valve  slides  freely.  The  main  valve  is  of  the  balanced 
air-thrown  spool  type,  with  wearing  surfaces  ground  to  a  plug 


266      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

tit  in  a  reamed  valve  chest.  One  end  or  other  of  the  auxihary 
valve  projects  slightly  into  the  cyhnder  bore  and  is  pushed  or 
lifted  by  the  piston  in  its  travel.  This  movement  is  perfectly 
free  and  very  short — only  enough  to  uncover  a  small  port  which 
releases  pressure  from  one  end  of  the  main  valve;  full  pressure 
on  the  other  end  then  throws  this  main  valve,  opening  wide 
the  main  port  and  admitting  full  pressure  to  the  piston  for  the 
return  stroke. 

The  auxiliary  valve  is  simply  a  trigger  which  releases  the 
main  valve.  It  is  accurately  machined  from  the  best  tool 
steel,  and  is  hardened.  Being  very  light,  its  impact  cannot 
injure  or  retard  the  piston;  nor  is  there  any  of  that  crowding 
of  the  piston  against  the  opposite  cylinder  wall  which  has  been 
such  a  fruitful  source  of  trouble  in  ordinary  tappet  drills  and 
responsible  for  the  rapid  wear  of  rings,  pistons  and  cylinders 
in  machines  with  ordinary  unbalanced,  hard-moving  tappet 
motions.  Pressure  being  on  the  back  of  the  auxihary  valve, 
continued  wear  only  improves  its  seating.  Its  action  is  quick, 
positive  and  perfectly  free. 

The  main  valve  is  accurately  ground  from  hardened  tool 
steel  and  is  protected  by  buffers  at  the  end  of  its  travel;  breakage 
is  unknown.  Being  perfectly  balanced,  it  moves  freely  with 
little  wear,  and  the  full  port  opening  is  secured  almost  instantly. 
The  combined  action  of  these  two  valves  is  such  that  admission 
and  exhaust  ports,  instantly  opened,  retain  full  opening  to  the 
end  of  the  stroke.  There  is  therefore  no  cushion  pressure  to 
retard  the  stroke  and  diminish  the  blow;  and  for  a  given  diameter 
of  cylinder  and  a  given  weight,  this  is  by  all  odds  the  most 
powerful  drill  made. 

The  "  Sergeant "  drill  has  a  wide  variation  of  stroke,  secured 
simply  by  "  cranking  "  the  machine  forward,  without  any 
valves  or  other  regulating  devices.  The  blow  is  absolutely 
dead,  and  no  machine  of  equal  cylinder  diameter  can  match 
it  in  its  effective  penetrating  quality.  The  ability  of  this  drill 
to  run  on  a  very  short  stroke  is  of  special  advantage  in  start- 
ing a  hole  on  an  oblique  surface  and  in  avoiding  a  glancing 
blow,  with  consequent  breakage  of  the  starter  shanks;    it  also 


APPENDIX  T  207 

admits  of  the  hole  being  quickly  started  without  "  funneling  " 
or  "  rifling."  This  feature  is  of  vital  importance  under  many 
drilHng  conditions — such  as  working  through  seams,  in  shelly 
or  caving  material  where  pebbles  fall  under  the  bit.  in  crevices 
or  alternate  layers  of  hard  and  soft  rock,  and  in  many  other 
circumstances  familiar  to  drill  runners  and  likely  to  be  encoun- 
tered anywhere.  The  drill  also  "  muds  "  or  cleans  the  cuttings 
out  of  the  hole  in  a  most  effective  manner. 

Another  most  important  advantage  of  the  variable  stroke 
of  the  "  Sergeant  "  drill,  and  one  appealing  to  the  practical  man, 
is  that  it  makes  possible  the  use  of  odd  steels  which,  by  wear 
or  breakage,  have  become  of  uneven  length.  Some  other  drills 
cannot  use  steels  differing  more  than  2  inches  from  standard 
lengths.  Steels  shortened  as  much  as  5  inches  can  be  used  with 
this  drill.  This  fact  allows  more  leeway  in  starting  the  machine 
after  changing  steels,  without  moving  the  setting,  wasting  time 
in  getting  an  odd  steel  shortened,  or  hunting  up  a  steel  of  the 
right  length.  Drills  of  other  types  are  compelled  to  start  on 
practically  full  stroke. 

Another  valuable  feature  of  design  in  this  drill  is  that  the 
valve  action  is  not  dependent  upon  the  condition  of  cylinder, 
piston  or  rings.  It  has  an  absolutely  positive  and  independent 
valve  movement.  Other  types  of  independent  valve  machines 
operate  well  only  so  long  as  the  piston  is  a  good  plug  fit  in  the 
cyUnder;  and,  cylinder  walls,  piston  and  rings  being  inevitably 
subject  to  wear  and  consequent  leakage,  the  valve  action  is 
soon  at  a  serious  disadvantage  and  requires  very  extensive 
repairs  or  entire  rebuilding.  The  auxiliary  valve,  in  striking 
contrast  to  this,  will  perform  its  functions  perfectly,  even  with 
a  loose  piston  or  with  the  rings  entirely  absent  from  the  machine. 
To  this  exclusive  feature  of  design  is  largely  due  the  sustained 
capacity  of  this  drill.  But  it  is  almost  unnecessary  to  state 
that  a  tight  piston  is  always  advisable  in  the  interest  of  highest 
efficiency  and  good  air  or  steam  economy. 

Remarkable  records  have  been  made  in  the  hardest  rock  by 
drills  of  this  type;  performances  just  as  remarkable  have  been 
noted  in  soft  and  medium  rocks — facts  leading  to  the  belief 


268      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

that  this  can  be  justifiably  called  an  "  all-around  "  drill.  For 
rapid  tunnel  driving  and  hard  service  anywhere  it  is  without 
doubt  the  best  machine  to-day.  It  is  a  rapid  and  economical 
drill  under  almost  any  condition,  except  where  its  dead,  stunning 
blow  loses  effect  in  "  springy  "  or  elastic  material.  The  best 
results  are  always  secured  with  live,  active  air;  but  dry  steam 
brings  out  a  good  performance  also.  It  is  a  simple,  rugged 
machine,  and  the  frequent  remark  about  it  is  that  "  any  black- 
smith can  keep  it  in  good  running  order."     All  bolts  and  threads 


IngersoU-Rand  "  Universal  "  Tripod  for  Rock  Drills. 

are  standard;  there  is  nothing  "  special  "  about  it.  In  long- 
continued  service  under  the  most  severe  conditions  its  repairs 
have  been  found  to  be  less  than  upon  any  other  model  of  drill; 
while  recent  improvements  in  details  have  added  to  its  ecomony 
and  power. 

Rock  Drill  Mountings.  The  essentials  of  a  successful 
tripod  are:  a  flexibility  adapting  it  to  rough  surfaces,  a  wide 
and  ready  adjustment,  and  a  great  strength  and  rigidity  in 
service.  The  "  Sergeant  "  tripod,  here  illustrated,  meets  the 
requirements.  All  adjustments  are  independent,  and  a  single 
wrench   fits   all  nuts.     At  all  joints  a  wedge  effect  is  secured 


APPENDIX    I 


209 


IT 


by  the  use  of  cone-shaped  clamping  surfaces  of  large  area. 
The  legs  are  te-lescopic  and  the  weights  can  be  adjusted  at  any 
height. 

In  tunnel  work,  in  shaft  sinking,  in  mining,  and,  to  a  more 
limited  extent,  in  quarry  work,  the  column  or  bar  has  become 
an  indispensable  form  of  drill  mounting. 
It  is  simply  an  extra  heavy  wrought  steel 
tube,  carrying  at  one  end  a  rosette-shaped 
head,  and  at  the  other  one  or  two  jack 
screws  suitably  mounted.  One  or  more 
column  arms  may  be  mounted  and  clamped 
on  the  column,  carrying  the  drills;  or,  the 
drill  may  be  mounted  directly  on  the 
column.  In  either  case,  a  safety  clamp, 
secured  on  the  column  below  the  column 
arm  or  drill,  prevents  the  latter  from 
falling  when  the  clamp  bolts  are  loosened 
to  swing  around  the  column  in  changing 
steels.  Under  this  general  classification 
there  are  three  distinct  types,  described  as 
follows : 

In  tunnel  work,  with  a  heading  or  drift 
of  8  or  9  feet,  a  double-screw  column  is  the 
usual  mounting  for  drills.  Each  column 
may  carry  two  or  more  machines,  the  number 
of  the  latter  required  depending  upon  the 
size  of  heading  and  the  rate  of  advance. 
In  tunnels  27  feet  wide  and  24  feet  high, 
with  8-foot  headings,  it  is  customary  to  use 
four  drills  on  columns  in  the  heading  and 
two  on  tripods  on  the  bench.  In  tunnels  15  feet  wide  and  18 
feet  high,  with  8-foot  headings,  three  drills  are  ordinarily  used. 
The  double-screw  column  has  two  jack  screws  at  the  base, 
which  give  great  security  and  rigidity.  The  drill  on  the  column 
has  a  great  range  of  adjustabihty;  it  may  be  shifted  sideways 
on  the  arm,  and  the  arm  may  be  raised  or  lowered  or  swung 
completely  about  the  column. 


IngorsoU-Rand  Double- 
Scivw  Column. 


270 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


The  single-screw  column  or  shaft  bar  is  a  mounting  designed 
for  rapid  and  economical  shaft  sinking.  The  various  lengths 
of  bar  accommodate  various  shaft  openings.  This  device  has 
but  one  jack  screw,  which  is  fitted  with  a  patent  lock  nut, 
giving  perfect  security  against  working  loose.  For  shafts 
less  than  8  feet  across,  the  bar  should  carry  but  one  drill.     For 

larger  shafts,  two  drills  on  a  bar 
may  be  used,  the  latter  being 
supported  by  center  legs.  The 
arms  permit  of  lengthening 
or  shortening,  can  be  swiveled 
to  any  position,  or  may  be 
swung  completely  over  to  drill 
on  both  sides  of  the  bar.  Drills, 
arm  and  bar  may  be  folded 
compactly  together  and  re- 
moved bodily  when  a  blast  is 
to  be  fired. 

The  stoping  bar  is  simply 
a  short  bar  upon  which  the 
drill  is  mounted  directly  with- 
out any  column  arm.  It  has 
one  jackscrew,  secured  by  a 
lock  nut,  and  is  designed  for 
stoping  work  in  mines  or  for 
light  drilling  in  a  drift  or 
heading. 

Hammer  or  Plug  Drills. 
The  hammer  drill  or  "  buzzer  " 
is  undoubtedly  playing  a  most  important  part  in  the  economi- 
cal working  of  modern  mines.  It  has  passed  through  a  long 
and  expensive  development  period.  It  is  natural  that  in  the 
creation  of  an  entirely  new  device  experience  alone  can  work 
out  the  best  features  both  of  practical  design  and  of  prac- 
tical application  of  the  tool.  Many  designs  have  failed;  and 
while  the  correct  principles  were  being  traced  out,  much  has 
been  learned  as  to  the  proper  field  of  use  of  the  hammer  drill, 


Ingersoll-Rand  Double-Screw  Column 
with  Arm  and  Saddle  for  Rock  Drill. 


APPENDIX   I 


271 


builders  and  users  alike  learning  its  limitations  and  its  possi- 
bilities. 

The  standard  piston  rock  drills  have  no  equal  in  the  class 
of  work  for  which  they  are  properly  adapted,  viz.,  the  drilling 
of  comparatively  large  and  deep  holes  at  all  angles.  But  as 
the  diameter  and  depth  of  hole  best  suited  to  move  a  given  amount 
of  rock  diminish,  a  point  is  reached  where  the  economical  field 


"  Little  Giant "  Drill  on  Single-screw  Column  or  Shaft  Bar. 


of  the  standard  drill  merges  into  one  best  covered  by  the  hammer 
drill.  The  dividing  line  is  reached,  in  mining  work  for  instance, 
where  narrow  stopes  are  encountered,  where  upraises  have  to 
be  driven,  as  in  the  caving  system,  in  underhand  stoping, 
where  a  thin  vein  must  be  worked  with  a  minimum  breaking: 
of  waste  rock,  or  wherever  small,  comparatively  shallow  holes 
(usually  "up"  holes),  easy  placing  of  the  machine  used  and 
economical  drilling  through  reduced  "  dead  time  "  become 
determining  factors.  This  means  that  as  large  a  proportion 
of  the  time  as  possible  shall  be  spent  in  actual  drilling 
rather  than  in  setting  up  and   moving.      From    the  line  here 


272 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


defined  the  field  of  the  hammer  drill  extends  down  to  the 
drilling  of  the  smallest  holes  for  trimming,  pop  shots  and 
similar  work. 

The  diameter  of  the  hole  has  everything  to  do  with  the 
question  of  economical  rock  drilhng.  With  the  hammer  drill, 
as  with  all  other  classes  of  rock  drills,  the  drilling  speed  and 

consequent  cost  of  air  and  labor, 
and  the  strains,  breakage  and  en- 
durance of  steel  and  parts  are 
greatly  aft'ected  by  the  diameter 
of  the  hole  drilled.  No  attempt 
should  be  made  to  drill  large  holes 
with  these  small  machines,  but 
the  smallest  holes  which  will  break 
the  ground  should  be  adhered  to, 
as  in  hand  drilling.  But  failure  to 
appreciate  this  simple  point  is  at 
the  root  of  most  of  the  complaints 
of  high  cost  of  work  with  an}-  class 
of  rock  drills. 

The  term  "  hammer  drill  "  is 
here  used  as  distinguishing  those 
light  machines  in  which  the  steel 
is  not  attached  to  and  reciprocated 
with  the  piston,  but  is  struck  by 
the  hammer  or  piston,  as  in  hand 
drilling.  They  are  usually  used 
without  any  mounting,  but  are 
handled  and  directed  simply  by  the  operator's  hands.  It  is 
to  be  noted,  however,  that  there  are  instances  w^here  these 
machines  are  also  used  with  fixed  mountings.  This  classifica- 
tion includes  not  only  the  ordinary  hand  tool — the  original 
txpe  of  "  plug  drill  '' — but  also  the  telescope  air-feed  machines 
for  "up"  holes. 

The  hammer  drill  is  rapidly  supplanting  hand  drilling  in 
every  field  purely  on  the  ground  of  lower  cost  per  foot  of  hole 
drilled.     This  tj'pe  is  not  for  one  moment  to  be  considered  as  a 


"  Imperial  "  Hand  Hammei-  Drill. 


APPENDIX    I 


273 


substitute  for  the  standard  piston  rock  drill.  Its  principal 
application  is  in  the  class  of  work  which  the  larger  machine 
never  even  attempted  to  handle,  for  most  of  the  driUing  in  many 
mines  and  contract  jobs  is  still  done  by  hand. 


"Cro^Ti"  Hand  Hammer  Drill. 


The  hammer  drill  is  extremely  simple,  having  only  one, 
or  at  the  most  two,  moving  parts.  This  means  a  steady  reliabil- 
ity and  ease  of  up-keep,  with  low  repair  costs  in  the  best  tvpes. 

Requiring  but  a  moment  to  change  steels  or  start  a  new 


274      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

hole,  probably  70  to  90  per  cent  of  the  work  paid  for  is  applied 
in  actual  drilling,  while  with  an  ordinary  piston  drill  usually 
not  more  than  two  thirds  and  often  less  than  half  the  time  is 
actual  drilling  time.  This  is  a  most  important  point  in  work 
where  a  large  number  of  small,  shallow  and  carefully  placed 
holes  are  required. 

The  hammer  drill  can  be  used  in  extremely  close  quarters — 
places  where  no  piston  drill  with  a  fixed  mounting  could  be  used, 
or  even  a  hand  hammer  swung.  Wherever  a  man  can  go  he 
can  take  a  hammer  drill  with  him.  It  is  truly  a  "  handy  " 
machine,  easily  carried  an^^where  under  all  conditions. 

The  air  consumption  of  hammer  drills  is  about  one-half 
that  of  the  smallest  piston  drill,  meaning  that  a  given  com- 
pressor plant  will  run  twice  as  many  hammer  drills,  doing 
probably  twice  the  work,  and  often  more,  in  certain  conditions; 
or,  the  initial  power  and  plant  investment  for  a  hammer  drill 
outfit  to  do  a  given  work,  as  in  prospecting  or  development, 
need  be  much  less  than  that  required  for  an  equipment  of  piston 
drills. 

No  special  skill  is  required  to  operate  a  hammer  drill,  and 
herein  lies  one  of  its  greatest  advantages.  Only  a  skilled  machine 
man  can  overcome  a  "  fitchered  "  hole,  start  a  difficult  hole,  or 
determine  the  proper  feed  and  stroke,  thus  getting  maximum 
results  with  the  piston  drill.  But  a  half  day's  work  will  famil- 
iarize any  intelligent  laborer  with  a  hammer  drill.  One  skilled 
drill  man  can  direct  or  "  point  "  the  holes  for  half  a  dozen  or 
more  hammer  drills — a  most  important  item  where  good  men 
are  hard  to  get. 

It  is  a  fact  that  one  hammer  drill  will  average  an  equivalent 
of  six  to  fifteen  hand  drillers.  Good  labor  is  every  year  more 
scarce.  If  ten  hammer  drills  will  do  the  work  of  one  hundred 
men,  they  are  certainly  a  good  investment.  With  a  limited 
force  provided  with  these  drills  ten  times  the  drilling  can  be 
done  and  the  footage  correspondingly  increased,  thus  getting 
cheap  machine  results  in  a  short  time  which  would  otherwise 
take  much  longer. 

This  advantage  goes  still  farther.     ]Much  of  the  economy 


AIM'KNDIX    I 


275 


of  blasting  depends  upon  the  holes  being  properly  and  skillfully 
placed  to  bring  out  the  maximum  quantity  of  rock  with  the 
minimum  powder  charge  and  with  the  minimum  amount  of 


"  Crown  "  Plug  Drill  \\-ith  Air  Jet  for  Blo^"ing  away  Dust. 


undesirable  waste  rock.  It  is  certainly  true  that  the  average 
skill  of  ten  selected  hammer  drill  men  will  be  higher  than  that 
of  a  gang  of  one  hundred  hand  drillers.  The  importance  of  this 
point  in  its  bearing  on  low  costs  and  improved  operating  con- 
ditions will  be  appreciated  by  every  contractor. 


276 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


The  experience  of  the  most  careful  users  has  shown  that  the 
hammer  drill  brings  about  a  most  important  reduction  in  the 
cost  of  explosives.  The  average  powder  man  will  load  a  hole  to 
the  Hmit,  regardless  of  whether  so  much  powder  is  needed  or 
not.  The  small  hole  made  by  the  hammer  drill  reduces  the 
likelihood   of   overcharged  holes   or   "  over-shooting." 

The  hammer  drill  in  the  quarry  is  usually  of  the  plain  hand- 


"  Imperial"  Valveless  Telescope  Feed  Hammer  Drill  or  Stoper. 

tool  type,  and  finds  its  apphcation  in  drilling  plug-and-feather 
holes,  pop  holes,  block  holes  and  anchor  bolt  holes. 

In  mining  and  tunneling  practice  the  prevailing  type  is 
the  air-feed  hammer  with  automatic  telescope  feed,  though  the 
hand  tool  has  also  a  limited  apphcation.  Its  work  here  is 
drilling  in  upraises,  stoping,  following  narrow,  rich  veins, 
squaring  up,  cutting  hitches,  trimming  walls,  and  the  occa- 
sional drilling  of  "  pop  "  holes  and  block  holes. 

In  the  coal  mine  the  hammer  drill  is  useful  in  cutting  ditches, 
sumps,  etc.,  levelling  floors,  taking  off  rolls  or  "  horse  backs," 
taking  down  roof,    taking  up  floors,    brushing  entries,  cutting 


APPENDIX  1 


277 


through  spars,  drilling  holes  for  trolley  hangers  or  engineering 
points,  cutting  trolley  cross-overs,  etc. 

The  work  of  the  hammer  drill  in  contracting  replaces  "  mud 
capping  "  and  includes  block  holing,  "  pop  "  shooting,  drilhng 
anchor  bolt  holes,  breaking  up  old 
concrete  or  masonry  foundations, 
piers,  walls,  etc.,  dislodging  the  sub- 
structure of  old  cable  or  conduit  rail- 
ways, and  removing  rock  in  sewer, 
gas,  water  main  or  conduit  trenches, 
cellars,  shafts,  wells,  etc. 

A  feature  which  cannot  be  too 
strongly  insisted  upon  is  the  question 
of  proper  bits  for  the  hammer  drill. 
Neglect  of  this  point  alone  often 
determines  the  whole  difference  be- 
tween success  and  failure.  The 
hammer  drill  depends  upon  a  large 
number  of  relatively  light  blows.  A 
clumsy  tool  or  improperly  dressed 
bit  may  put  a  hole  down  by  main 
strength  and  brute  force  with  a  pis- 
ton drill.  But  with  a  hammer  drill 
striking  up  to  100,000  blows  an 
hour,  or  1,000,000  per  day,  a  very 
slight  difference  in  the  quality  of  the 
steel,  the  exact  angle  of  the  cutting 
edges,  the  proper  clearance  and  hard- 
ening, the  number  of  cutting  edges, 
whether  one  or  eight,  all  are  points 
which  may  make  all  the  difference  in 
the  world.  Disappointment  or  en- 
thusiasm rests  largely  on  these  very 
points,  and  they  should  be  deter- 
mined exactly  by  intelligent  experiment  for  every  kind  of 
rock.  The  conditions  thus  discovered  should  then  be  posi- 
tively maintained. 


Butterfly  Valve"  Telescope 
Feed  Hammer  or  Stoping 
Drill. 


278      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

The  IngersoU  Drill  and  the  Cameron  Pump.      It  was  in  a 

little  shop  on  the  corner  of  Second  Avenue  and  Twenty-second 
Street,  New  York,  that  both  the  IngersoU  drill  and  the  Cameron 
pump  originated,  and  the  manufacture  of  both  began  under 
the  same  roof.  The  late  Henry  C.  Sergeant,  who  is  admitted 
to  have  done  more  in  the  invention  and  development  of  the  rock 
drill  than  any  other  person,  designed  the  first  really  successful 
IngersoU  drill,  getting  his  fundamental  ideas  of  the  valve  motion 
from  Mr.  A.  S.  Cameron.  This  was  at  a  time  when  a  reciprocat- 
ing engine,  like  a  pump  or  a  rock  drill,  with  no  crank  shaft  to 
carry  it  over  the  center,  was  practically  unknown.  The  first 
machines  of  this  class  were  built  on  steam  engine  lines,  the 
valve  itself  being  mechanically  connected  with  or  operated  by 
the  piston.  In  the  first  IngersoU  drill,  as  in  the  first  direct- 
acting  pumps,  when  the  piston  reached  the  end  of  the  stroke 
it  reversed  the  valve  by  direct  mechanical  contact  with  knuckle 
joints,  rods  or  other  devices,  which  intervened  between  the 
piston  and  the  valve. 

Here  is  where  great  credit  is  due  Mr.  A.  S.  Cameron.  He 
was  seeking  to  perfect  a  pump  which  could  be  used  in  rough 
places  where  exposed  parts  were  liable  to  wear  or  injury.  He 
also  wanted  to  design  a  valve  which  would  open  a  large  port 
at  the  end  of  the  stroke  the  instant  that  the  piston  reached  a 
certain  point.  This  was  hardly  possible  with  a  mechanically 
moved  valve  without  excessive  shock  and  wear.  Cameron's 
invention,  therefore,  was  to  place  a  small  tappet  or  knuckle 
in  each  cylinder  head  of  the  pump,  which  should  serve  as  a 
trigger  to  trip  and  open,  through  contact  with  the  piston,  a  small 
port  connecting  with  one  end  or  the  other  of  the  valve 
chamber.  The  valve  itself  was  submerged  in  live  steam  pres- 
sure, equal  on  both  ends,  and  hence  when  this  tripping  action 
took  place  it  reduced  the  pressure  on  one  end  so  that  then 
the  full  pressure  on  the  other  end  caused  it  to  reverse.  In 
order  to  do  this  with  the  minimum  shock  on  the  tappet,  and  also 
taking  into  consideration  the  importance  of  having  a  small  port 
controlled  by  such  action,  Mr.  Cameron  used  a  plunger  piston 
which  in  turn  overlapped  the  valve  itself,  this  plunger  piston 


APPENDIX  I  279 

having  an  area  on  each  end  which  might  be  more  or  less  accord- 
ing to  the  resistance  of  the  valve  to  the  action  of  shding  on  its 
seat.  The  valve  itself  was,  and  still  is,  a  slide  valve,  which, 
as  everybody  knows,  rests  tightly  upon  its  ports  and  does  not 
leak  through  wear. 

Sergeant  had  a  problem  more  difBcult  than  Cameron,  because, 
in  the  first  place,  the  piston  speed  of  a  pump  is  only  about  loo 
feet  per  minute,  while  that  of  a  rock  drill  is  four  times  as  great. 
This  high  speed  made  it  difficult  to  use  any  kind  of  a  tappet 
trigger,  and,  in  order  to  get  the  quickest  action  of  the  valve, 
Sergeant  sought  to  avoid  the  use  of  the  slide  valve  and  to  use 
the  plunger  or  valve-moving  device  of  Cameron  as  the  valve 
itself.  In  doing  this  he  ran  against  another  difficulty:  the 
valve,  in  order  to  be  tight  on  its  seat,  would  press  so  hard  that 
the  speed  of  the  drill  became  sluggish,  and  to  remedy  this  he 
ran  a  bolt  through  the  center  of  the  valve,  which  relieved  it 
of  a  certain  portion  of  this  pressure. 

Instead  of  the  tappet  trigger.  Sergeant  moved  his  valve 
by  causing  the  piston  of  the  drill  to  uncover  passages  leading 
alternately  to  each  valve  end.  Here  we  have  the  identical 
principle,  so  far  as  valve  movement  is  concerned,  which  is 
embodied  in  the  Cameron  pump — namely,  an  equal  pressure 
on  both  ends  of  the  valve,  and  the  valve  moving  in  consequence 
of  reduction  of  that  pressure  on  one  end  and  the  other  alternately, 
the  action  itself  being  determined  by  the  strokes  of  the  piston. 
No  better  evidence  is  needed  of  the  success  of  this  valve  action 
than  the  fact  that  the  IngersoU  "  Eclipse  "  drill  and  the  Cameron 
pump  are  at  work  to-day  with  valves  of  this  type. 

The  community  of  interests  between  Cameron  and  IngersoU 
has  extended  from  this  inception  to  the  present  day.  The 
castings  for  the  first  air  compressors  of  the  IngersoU  make 
were  made  in  the  Cameron  foundry  on  East  Twenty-second 
Street.  For  many  years,  and  until  the  IngersoU  works  were 
moved  to  Easton,  Pa.,  castings  were  made  by  Cameron. 

Adam  Scott  Cameron  was  the  youngest  of  four  brothers, 
all  of  whom  took  up  mechanical  pursuits.  While  a  youth 
serving  his  apprenticeship,  he  was  a  student  at  Cooper  Institute, 


280      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

giving  his  nights  and  spare  time  to  study  and  research.  He 
graduated  with  honors,  and  at  once  applied  himself  to  mechan- 
ical matters.  He  was  early  engaged  in  building  the  Sewall 
and  Cameron  crank-and-fly-wheel  pump,  which  during  the 
Civil  War  was  in  demand  by  the  United  States  Navy  and  the 
merchant  marine.  At  the  close  of  the  war  the  call  for  these 
pumps  fell  off,  so  that  Mr.  Cameron  turned  his  attention  to  the 
design  of  a  pump  of  greater  adaptability  and  more  general 
apphcation.  The  standard  Cameron  pump  was  the  result, 
its  acorn-shaped  air  chamber  being  his  trademark  and  con- 
tinuing up  to  the  present  time.  He  died  at  an  early  age,  but 
before  death  he  stamped  his  ability  and  force  of  character  upon 
the  mechanical  engineering  of  his  age. 


APPENDIX  J 

TUNNEL  CARRIAGE  FOR  DRILLING;    ELECTRIC-AIR  DRILL 

The  illustrations  herewith  show  two  types  of  tunnel  carriage 
recently  brought  out  by  the  Ingersoll-Rand  Company.  The 
object  of  this  device  is  to  save  time  in  setting  up  the  drills  in 
the  heading,  in  removing  them  for  blasting,  and  in  starting 


Fig.  1 

drilling  again  after  the  blast,  without  serious  interference  with 
the  mucking  operations.  The  illustrations  are  almost  self- 
explanatory. 

It  will  be  noted  that  there  is  a  truck  with  flanged  wheels 
running  on  the  ordinary  tunnel  track  for  muck  cars.  Upon  this 
truck  and  arranged  to  swing  in  a  vertical  plane,  is  a  long  arm 
of  structural  steel  shapes  with  an  upright  screw  rod  at  the 
rear  which  is  run  out  to  roof  and  floor  of  the  tunnel,  fixing 
the  arm    rigidly  in  position.      Upon    this    arm    is    a  carriage 

281 


282 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


moved  forward  or  back  by  a  chain  and  crank;  and  this 
carriage  supports  a  heavy  drill  bar  swiveling  in  a  horizontal 
plane.  This  bar  carries  the  drills  and  has  jack  screws  at 
its  ends  which  are  run  out  against  the  walls  of  the  heading. 
A  drop  support  beneath  the  long  arm  gives  fruther  rigidity  to 
the  mounting. 

Fig.  I  shows  the  tunnel  carriage  ready  to  be  run  into  the 
heading,  with  the  drills  swung  sidewise,  the  drill  bar  turned 
parallel  with  the  arm,  and  the  whole  drawn  back  over  the 
truck.     All  supports  are  free.     Fig.   2  shows  the  tunnel  car- 


FiG.  2 


riage  in  position  for  operation,  with  supports  set.  It  will  be 
noted  that  there  is  ample  room  beneath  the  arms  and  in  front 
of  the  truck  to  permit  mucking  to  proceed  while  drilling  is 
going  on.  Standard  drills  are  used,  held  in  saddles  on  the  drill 
bar. 

It  will  be  readily  seen  that  this  type  is  susceptible  of  adap- 
tation to  various  conditions.  Fig.  3,  for  instance,  shows  a 
modification  in  which  the  long  swinging  arm  is  dispensed  with 
and  the  vertical  adjustment  of  the  drill  bar  is  secured  by  means 
of  a  large  central  screw.  The  drills  can  be  swung  on  the  bar 
to  drill  holes  in  any  position— up,  horizontal,  down,  or  side 
holes.     While  the  illustrations  show  a  4-drill  bar,  it  is  evident 


APPENDIX  J 


283 


that  a  longer  bar  for  more  drills  could  readily  be  used  on  this 
carriage. 

The  Electric- Air  Drill.  By  W.  L.  Saunders.  Many  members 
of  the  A.I.M.E.,  who  participated  in  the  visit  made,  during 
the  Bethlehem  meeting  of  February,  1906,  to  the  shops  of  the 
Ingersoll-Rand  Company,  at  Phillipsburg,  N.  J.,  inspected 
with  interest  the  new  Electric-Air  drill,  which  the  company 
had  set  up  for  the  purpose  of  showing  it  in  actual  operation  to 


Fig.  3 


American  mining  engineers.  At  the  request  of  the  Secretary 
of  the  Institute,  I  promised  at  that  time  to  prepare  a  paper  for 
our  Transactions,  describing  the  construction  and  advantages 
of  the  machine.  But  such  a  paper  would  then  necessarily  have 
contained  much  that  was  only  expected  or  claimed  by  the 
designers  and  manufacturers  of  the  drill,  and  not  yet  incon- 
trovertibly  proved  by  varied  and  ^  long-continued  practice. 
However  moderate  such  statements  might  have  been,  the>- 
would  have  given  inevitably  to  the  paper,  to  some  extent  at 


284      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

least,  the  air  of  a  prospectus,  rather  than  of  a  technical  contribu- 
tion. I  therefore  decided,  with  the  secretary's  approval,  to 
postpone  the  writing  of  the  promised  paper  until  it  could  set 
forth  the  results  of  adequate  actual  practice,  as  well  as  the  latest 
details  of  construction,  etc.,  based  upon  practical  experience. 
That  period  has  now  arrived.  The  Electric-Air  drill  has  been 
exhaustively  tested  in  the  field,  under  varied  and  arduous 
conditions,  and  upon  the  hardest  rocks.  It  is  now  fairly  in  the 
field;  its  merits  and  performances  are  matters  of  unimpeachable 
record,  and  its  place  among  estabHshed  competitors  can  be 
definitely  determined. 

As  a  representative  of  the  Ingersoll-Rand  Company,  as  well 
as  a  member  of  the  Institute,  I  may  be  permitted  to  add  that 
my  company,  being  largely  interested  in  the  manufacture  of 
air  compressors  and  machinery  driven  by  compressed  air,  has 
no  desire  to  injure  its  own  business  by  claiming  for  this  new 
machine  that  it  should  immediately  supersede  all  existing 
applications  of  pneumatic  transmission  of  power  for  drilhng. 
On  the  other  hand,  if  we  had  not  satisfied  ourselves  that  it  has 
proved  itself  the  best  for  given  conditions,  the  company  would 
not  have  risked  its  reputation  by  introducing  it,  and  I,  as  a 
member  of  the  Institute,  would  not  have  written  this  paper. 

In  former  contributions  I  have  discussed  the  use  of  com- 
pressed air,  and  opposed,  to  some  extent,  the  claims  of  the 
advocates  of  electrical  power  transmission  in  mining.  I  need 
not  now  retract  any  opinion  thus  declared.  ]\Iany  features 
of  electrical  transmission  are  undoubtedly  convenient  and  eco- 
nomical; but  the  direct  apphcation  of  the  electric  current  in 
rock  drilling  has  long  been  a  baffling  problem;  of  which,  in  my 
judgment,  the  machine  here  described  has  furnished  the  first, 
and  thus  far  the  only,  satisfactory  solution,  by  combining  the 
acknowledged  advantages  of  air-driven  percussion  with  the 
acknowledged  advantages  of  electric  power  transmission,  while 
avoiding    the    acknowledged    disadvantages    of   both    systems. 

The  Electric-Air  drill  is  correctly  designated;  it  is  not  an 
electric  drill,  but  an  air  drill,  more  completely  an  air  drill  than 
any  other  in  existence,  because  it  can  be  driven  by  air  only. 


APPENDIX  J 


285 


and  not,  like  other  air  drills,  by  steam  also.  Yet,  while  it  is 
thus  distinctly  air  operated,  the  power  of  transmission  is  electric, 
and  the  sole  connection  of  the  drill  with  the  power  house  is 
made  by  means  of  the  electric  wire,  air  compressors  and  pipe 
lines  being  entirely  dispensed  with. 

The  illustration  gives  a  general  idea  of  the  apparatus.  It 
shows  a  rock  drill  which  at  first  glance  looks  quite  like  the 
famiHar  air  or  steam-driven  drill,  mounted  in  the  usual  way  and 
doing  the  same  kind  of  work.     Very  near  the  drill,  and  con- 


Section  of  "Electric-Air"  Drill  and  Pulsator. 


nected  to  it  by  two  short  lengths  of  hose,  is  a  small  air  compres- 
sor, or,  more  properly,  a  pulsator,  mounted  upon  a  httle  truck. 
This  constitutes  the  entire  apparatus  of  a  single  drill.  Each 
drill  is  accompanied  by  its  individual  pulsator  in  the  same  way, 
and  each  pulsator  is  connected  to  the  line  of  wire  from  the 
power  house. 

The  usual  drill  shell  is  employed,  and  this  may  be  mounted 
upon  tripod,  bar  or  column,  according  to  the  work.  The  drill 
cyUnder  fitted  to  slide  in  the  shell  is  moved  forward  or  backward 
by  the  feed  screw.  The  cyhnder  is  as  simple  as  can  be  imagined: 
a  straight  bore  with,  at  each  end,  a  large  opening  and  a  boss  to 


286      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

which  fo  attach  the  hose.  The  piston  also  is  plain,  much  short- 
ened in  the  body,  with  a  large  piston  rod  which  has  a  long 
bearing  in  a  sleeve  elongation  of  the  cyhnder. 

Upon  the  truck  is  mounted  an  electric  motor,  geared  to  a 
horizontal  shaft  with  i8o-degree  cranks,  which  drive  two  single- 
acting  trunk  pistons,  making  alternate  strokes  in  vertical  air 
cylinders.  One  of  these  air  cyhnders  is  connected  by  the  hose 
to  one  end  of  the  drill  cylinder,  and  the  other  end  of  the  cyl- 
inder is  connected  by  the  other  hose  to  the  other  air  cylinder. 
The  air,  therefore,  in  either  air  cyhnder,  in  its  hose  and  in  the 
end  of  the  drill  cyhnder  to  which  it  is  connected,  remains  there 
constantly,  playing  back  and  forth  through  the  hose  according 
to  the  movements  of  the  parts,  being  never  discharged  and  only 
replenished  from  time  to  time  to  make  up  for  leakage.  The 
propriety  of  calling  the  apparatus  a  pulsator  instead  of  a  com- 
pressor is  evident. 

The  essential  details  of  the  cycle  of  operation  will  be  easily 
understood.  We  may  assume,  to  begin  w^ith,  that  the  entire 
system  is  filled  with  air  at  a  pressure  of  30  or  35  pounds. 
This  pressure,  being  ahke  upon  both  sides  of  the  drill  piston, 
there  will  be  no  tendency  for  it  to  move  in  either  direction. 
If  now,  the  motor,  instead  of  being  at  rest,  is  assumed  to  be 
in  motion,  one  pulsator  piston  will  be  rising  in  its  cyhnder 
and  the  other  piston  will  be  descending  in  its  cyhnder;  and,  as 
a  consqeuence,  the  pressure  upon  one  side  of  the  drill  piston  will 
be  increased  and  the  pressure  upon  the  other  side  will  be  propor- 
tionately reduced,  this  difference  of  pressure  causing  the  drill 
piston  to  move  and  make  its  stroke.  Just  before  the  drill  piston 
reaches  the  end  of  its  stroke,  the  movement  of  the  pulsator 
pistons  is  reversed,  preponderance  of  pressure  is  transferred  to 
the  other  side  of  the  piston,  causing  a  stroke  in  the  other  direc- 
tion, and  so  on  continuously.  The  drill  thus  makes  its  double 
stroke,  or  at  least  receives  its  double  impulse,  for  each  revolu- 
tion of  the  pulsator  crank  shaft. 

This  is  a  sketch  of  the  general  principle  of  operation;  we  may 
now  consider  some  of  the  details.  The  drill  cylinder,  while 
generally  similar  to  that  of  the  air  or  steam  operated  drill,  is 


APPENDIX  J  287 

in  many  respects  quite  different,  and  especially  is  it  remarkable 
for  its  simplicity.  The  usual  operating  valve  chest,  the  valve 
and  the  complicated  means  for  operating  it,  the  main  air  ports 
and  the  intricate  little  passages  in  and  connected  with  the 
chest  are  all  conspicuous  by  their  absence,  and  nothing  takes 
their  place.  The  cylinder  heads  are  both  solid  and  both  fastened 
securely  in  place.  The  split  front  head,  the  yielding  fastenings 
for  both  heads,  the  buflfers,  the  springs,  the  side  rods,  etc., 
of  other  drills  are  all  banished.  The  cylinder  is  absolutely 
plain,  with  the  boss  at  each  end  to  which  the  hose  is  attached 
and  the  direct  openings  into  the  interior. 

The  piston  also  has  been  simplified.  The  rotation  device 
is  necessarily  retained,  but  the  enlargement  at  the  end  of  the 
piston  rod,  which  constituted  the  chuck  and  necessitated  the 
split  front  head,  is  not.  The  piston  rod  throughout  is  much 
enlarged,  and  a  simple  but  effective  self-tightening  chuck  is 
slipped  on  the  end  of  it. 

The  compressor  or  pulsator  cylinders  are  as  simple  as  the 
rest.  There  are  no  valves,  either  inlet  or  discharge,  and  there 
is  no  water  jacketing  nor  the  shghtest  need  of  any.  The  heat- 
ing of  the  air  upon  the  compression  stroke  is  compensated  for 
by  the  fall  of  temperature  accompanying  its  re-expansion,  so 
that  the  air  does  not  get  hot  and  does  not  heat  any  of  the  parts 
with  which  it  comes  in  contact. 

While  this  apparatus  as  a  whole  may  appear  complicated 
at  first  glance,  it  really  is  a  great  simplification,  and  the  parts 
got  rid  of  are  those  which  have  always  been  most  troublesome 
and  have  entailed  the  most  care  and  expense  to  maintain. 
The  drill  and  the  compressor  or  pulsator  are  each  the  simplest 
ever  built. 

There  are  some  minor  details  of  this  apparatus  with  which 
it  is  not  necessary  to  burden  this  paper,  and  which  would  involve 
tedious  explanation  that  all  would  not  follow.  In  our  descrip- 
tion of  the  principle  of  operation  of  the  drill  we  assumed  a 
mean  air  pressure  of  about  30  pounds  in  the  apparatus,  and 
it  may  be  asked  how  this  pressure  is  secured  and  maintained. 
When  the  pulsator  is  in  operation  the  air  pressure  in  the  cylin- 


288      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

ders  both  rises  above  and  falls  considerably  below  the  mean. 
If  at  a  certain  point  it  is  below  that  of  the  atmosphere,  then 
a  little  valve  provided  will  admit  more  or  less  air,  this  proc- 
ess continuing  until  sufficient  air  is  supplied.  In  the  begin- 
ning of  operations  the  influx  of  air  is  rapid,  so  that  no  time  is 
lost  in  getting  sufficient  pressure  to  begin  with.  The  admis- 
sion and  also  the  apportioning  of  the  relative  volumes  of  air 
to  the  two  ends  of  the  drill  cylinder  are  easily  adjusted  by  the 
operator. 

With  the  Electric- Air  drill  there  is  no  freezing  up  or  choking 
of  the  exhaust;  the  air  also  does  not  accumulate  moisture  and 
the  temperature  does  not  fall  to  the  freezing  point.  The  air 
does  become  and  remains  a  constant  vehicle  for  the  conveyance 
and  distribution  of  the  lubricant,  and  with  a  certain  amount 
of  oil  contributed  to  the  system  at  regular  intervals  the  problem 
would  be  how  to  prevent  its  reaching  every  working  part  rather 
than  the  reverse. 

The  length  of  hose  employed  seems  to  be  limited  to  about 
8  feet  for  each,  and  these  may  be  attached  to  either  side  of  the 
drill,  but  each  always  to  its  own  end  of  the  cylinder.  This 
length  of  hose  gives  all  necessary  hberty  for  the  location  of 
the  pulsator  truck  near  the  drill.  The  truck  is  of  steel,  with 
wheels  usually  made  for  the  standard  1 8-inch  mine  track,  but 
may  be  made  for  any  other  gage.  When  in  use  there  is  no 
necessity  for  any  care  in  leveHng  the  truck,  as  the  pulsator  will 
work  at  any  angle  at  which  the  truck  can  stand. 

The  motor  may  be  either  direct  or  alternating  current,  the 
latter  being  preferred  because  of  the  simple  mechanical  features. 
It  is  also  smaller  and  lighter,  a  simpler  and  hardier  machine 
and  more  nearly  fool-proof.  Several  different  speeds  may  be 
obtained  with  the  direct  and  alternating  current  motor,  full 
speed  for  steady  running  and  considerably  lower  speeds  for 
starting  a  hole  or  working  through  bad  ground,  with  imme- 
diate transition  from  the  one  speed  to  another  as  required. 
The  controller  is  on  the  top  of  the  motor,  and  the  operator 
at  the  drill  can  start,  speed  or  stop  the  motor  by  simply  pull- 
ing a  cord,  this  being  the  only  connection.     The  electrical  con- 


APPENDIX  J  289 

nection  ends  at  the  motor;  both  the  hose  and  the  cord  insulate 
the  drill  and  the  operator  is  never  exposed  to  the  current. 

The  Electric-Air  drill  strikes  a  blow  normally  so  much  harder 
than  that  of  the  air  drill  of  the  same  capacity,  that  in  many 
cases  it  is  found  advisable  to  dress  the  steels  blunter  or  thicker 
to  avoid  breakage.  The  practical  force  of  the  drill  was  not 
first  worked  out  in  computation,  but  has  been  demonstrated  in 
extensive  practice  and  protracted  experiment.  The  explana- 
tion has  come  later,  but  is  clear  and  sufficient. 

The  drill  piston  when  running  at  full  speed,  making  a  stroke 
for  each  rotation  of  the  pulsator  crank  shaft,  will  not  strike 
either  head.  The  hole  by  which  the  air  enters  the  cyUnder 
from  the  hose  is  not  located  at  the  extreme  end  of  the  cyHnder 
or  close  to  the  head,  but  a  certain  distance  away  from  it,  so  that 
when  the  piston  approaches  the  head  a  certain  portion  of  air 
is  enclosed  and  acts  as  a  cushion  which  first  checks  the  advance 
of  the  piston  and  then  shoots  it  back.  The  piston  thus  starts 
upon  its  working  stroke  impelled  by  a  certain  amount  of  force 
which,  we  may  say,  has  been  saved  over  from  the  preceding 
stroke  to  be  utilized  for  this.  The  piston  after  being  thus 
started  is  driven  forward  by  an  air  pressure  which  increases  as 
it  advances,  the  pulsator  piston  being  in  the  attitude  of  chasing 
and  gaining  upon  the  drill  piston  for  a  considerable  portion 
of  the  stroke,  while  in  the  case  of  the  ordinary  drill  piston, 
driven  by  a  constant  flow  of  air  which  it  runs  away  from,  the 
pressure  must  constantly  diminish  as  the  piston  speed  is  accel- 
erated. In  the  same  way  by  the  action  of  the  other  pulsator 
piston  the  opposing  pressure  upon  the  advancing  side  of  the 
drill  piston  is  a  diminishing  pressure  instead  of  the  constant 
atmospheric  resistance,  and  these  combined  cause  a  greater 
unbalanced  difference  of  pressures  upon  the  opposite  sides 
of  the  drill,  a  more  rapid  acceleration  of  the  piston  movement, 
and  a  consequent  higher  velocity  and  force  at  the  moment  of 
impact  of  the  steel  upon  the  rock. 

Perhaps  the  most  gratifying,  and  also  surprising,  revela- 
tion of  all  in  connection  with  the  Electric- Air  drill  is  the  now 
indisputable  fact   that  it   takes  only  one-third   to  one-fourth 


290 


SUBWAYS  AND  TUNNELS   OF  NEW   YORK 


of  the  power,  at  the  power-house,  to  drive  it  and  do  the  same 
work  as  a  rock  drill  of  equivalent  capacity.  This  is  accounted 
for  by  the  fact  that  the  same  air  is  used  over  and  over  and 
that  all  of  its  elastic  force  is  availed  of  in  both  directions, 
instead  of  exhausting  the  charge  for  each  stroke  at  full  pres- 
sure. There  are  also  no  large  clearance  spaces  to  fill  anew  at 
each  stroke,  as  these  spaces  are  never  emptied. 

A  curious  result  of  the  mode  of  driving  the  piston  of  the 


"Electric-Air  "  Rock  Drill  on  Quarry  Bar  Mounting. 

Electric-Air  drill,  and  another  valuable  feature  of  it  when  in 
operation,  is  found  in  the  trick  the  drill  has  of  "  yanking  " 
itself  free  when  the  bit  sticks  in  the  hole  and  of  going  on  with 
its  work  again.  When  the  bit  of  the  ordinary  air  or  steam 
driven  drill  sticks  in  the  hole,  that  is  the  end  of  it  as  far  as  the 
drill  is  concerned,  and  it  is  for  the  drill  runner  to  free  it  as  best 
he  may.  He  runs  the  feed  up  and  down,  hammers  the  steel, 
and  coaxes  things  in  various  ways  until  the  drill  gets  steadily 
running  again.  With  the  Electric-Air  drill  when  the  bit  sticks 
the  motor  and  the  pulsator  pistons  do  not  stop,  but  keep  running 


APPENDIX  J  291 

the  same  as  before.  This  means  that  if  the  drill  piston  is  mak- 
ing, say,  400  strokes  a  minute  it  will,  when  it  sticks,  receive 
per  minute  400  alternate  thrusts  and  pulls  with  full  force.  Noth- 
ing could  well  be  imagined  more  effective  for  freeing  the  bit, 
and  often  when  it  sticks,  and  before  the  runner  can  get  ready 
to  do  anything  about  it,  the  drill  is  running  right  along  again 
as  if  nothing  had  happened. 

The  coming  of  the  Electric-Air  drill  suggests  many  pos- 
sibilities, and  ominously  means  much  to  the  established  interest. 
It  necessarily  suggests  a  revolution  in  methods  and  sometimes 
perhaps  a  superseding  of  the  old  plants  throughout.  In  the 
working  of  the  new  drill  the  old  central  air  compressor  plants 
are  absolutely  worthless,  but  it  is  not  easy  to  imagine  any  gen- 
eral abandonment  of  them.  After  all,  the  result  may  probably 
be  that  the  new  drill  will  not,  to  any  great  extent,  drive  out 
the  old,  but  will  make  a  new  field  of  employment  for  itself,  and 
in  that  way  lead,  as  usual,  to  a  considerable  enlargement  of 
the  already  extensive  business  which  is  behind  it. 

As  has  been  shown,  the  Electric-Air  drill  is  as  far  as  can 
be  from  being  an  electric  drill,  but  it  makes  the  ordinary 
electric  current  nearly  everywhere  obtainable  immediately 
available  for  driving  it. 

In  the  planning  of  installations  which  are  new  throughout, 
the  Electric-Air  drill  is  to  be  most  seriously  considered.  The 
question  of  the  relative  final  cost  of  operating  this  drill,  or  any 
other,  is,  after  all,  the  decisive  one,  due  recognition  being  given 
to  the  peculiarities  of  each,  favorable  or  otherwise,  which  are 
not  computable,  but  which  still  have  their  weight  in  determining 
our  selections,  "  other  things  being  equal." 

When  the  Electric-Air  drill  is  operated  without  its  own 
generating  plant,  the  current  being  taken  from  a  large  power 
company,  some  very  low  figures  are  already  on  record.  At 
Idaho  Springs,  Colo.,  a  mine  shaft  was  put  down  67  feet  in  24 
shifts  and  the  total  power  cost  was  $24.00  for  the  entire  work. 

In  making  rock  excavations  for  building  purposes  in  New 
York  City  and  elsewhere,  steam  drills,  having  a  temporary 
boiler  installation,  are  frequently  used.     The  Electric-Air  drill 


292      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

not  only  avoids  the  expense  of  the  boiler  equipment,  but  will  do 
the  work  at  a  much  lower  cost,  the  current  being  supplied  by 
one  of  the  big  electric  power  companies.  Proceedings  oj  Am. 
Inst,  of  Mining  Engrs. 

Two  Electric-Air  Drill  Records,  with  Costs.  The  Brier  Hill 
Collieries  of  Crawford,  Tenn.,  have  been  using  one  of  these 
drills,  a  "  5-D,"  in  their  mines  for  about  eighteen  months  for 
drilling  holes  in  the  roofs  of  several  entries.  The  rock  varies 
from  slate  to  sandstone  and  conglomerate  rock;  and  Mr.  E. 
B.  Taylor,  general  manager  of  the  mines,  who  has  kindly  fur- 
nished us  with  the  information  regarding  this  drill,  states  that 
the  drilling  was  done  through  the  hardest  roof  he  had  ever 
encountered  in  thirty  years'  mining  experience. 

A  ''  5-D  "  drill  is  equivalent  to  an  Ingersoll-Rand  3|-inch 
air  drill,  and  has  a  stroke  of  a  little  more  than  8  inches.  It 
will  drill  a  1 6-foot  vertical  hole  from  i|  to  2f  inch  in  diameter. 
It  has  a  5i  h.p.  motor.  Such  a  drill  is  intended  for  the  heaviest 
work  in  large  tunnel  headings,  open  cut  work  in  quarries  or 
railroad  gradings,  in  shaft  sinking,  or  in  mining. 

During  sixteen  months'  work  with  this  drill,  holes  were 
drilled  in  the  roof  of  the  main  entry  of  one  mine,  a  distance  of 
600  lineal  feet;  in  driving  three  entries  of  another  mine,  a  dis- 
tance of  250  feet  in  a  new  haulway,  200  feet  in  the  second  left 
entry,  and  275  feet  in  the  third  left  entry. 

These  three  entries  were  driven  simultaneously,  the  drill 
being  moved  from  one  entry  to  another  as  it  was  needed.  One 
hole  was  drilled  in  the  roof  of  each  of  these  entries  each  day, 
the  average  depth  of  a  hole  being  7  feet.  It  took  the  drill  run- 
ner and  a  helper  from  twenty  to  thirty  minutes  to  unload  the 
drill  from  a  car  and  set  it  up,  while  the  hole  was  drilled  in  about 
twenty  minutes.  About  a  half  day  was  consumed  in  drilling 
the  three  holes  and  making  the  necessary  moves,  more  than 
three-quarters  of  the  time  being  taken  up  in  moving  and  setting 
up  the  drill. 

With  wages  for  the  drill  runner  at  $3.50  for  a  nine-hour 
day  and  $2.00  for  the  helper,  this  gives  a  labor  cost  of  13 
cents  per  lineal  foot  of  drilling.     Upon  one  occasion  the  crew 


APPENDIX  J  293 

drilled  seven  holes  in  a  nine-hour  shift,  aggregating  42  feet 
6  inches,  which  substantiates  the  cost  of  13  cents  per  lineal 
foot.  Mr.  Taylor  states  that  during  the  16  months  this 
work  was  going  on,  outside  of  sharpening  the  steel  bits,  not 
one  cent  was  spent  in  repairs  or  for  maintaining  the  drill — a 
rather  unusual  record  for  any  drill. 

The  Superior  Portland  Cement  Company  of  Superior,  Ohio, 
have  three  "  5-C  "  drills  at  work  in  their  limestone  quarries. 
We  are  indebted  to  Mr.  J.  B.  John,  manager  of  the  company, 
for  the  following  account  of  work  done  by  these  drills. 

The  vein  of  limestone  averages  about  8  feet  in  thickness. 
To  blast  out  this  limestone,  holes  6  feet  deep  and  25  inches  in 
diameter  are  drilled.  Each  drill  puts  down,  on  an  average, 
17  of  these  holes  per  day.  Thus  three  drills  do  306  Hneal  feet 
of  drilling  per  day.  There  is  blasted  out  an  average  of  500 
tons  of  limestone  per  day,  equivalent  to  1.4  lineal  feet  of  drilHng 
per  cubic  yard  of  rock  blasted,  place  measurement. 

With  wages  for  the  drill  runner  at  $3.50  per  day,  and  helper 
at  $2.00  per  day,  this  gives  a  cost  for  labor  for  drilling  of  5.4 
cents  per  Hneal  foot,  and  7.5  cents  per  cubic  yard  of  rock  blasted, 
which  is  a  very  low  cost,  accounted  for,  however,  by  the  rapid 
drilHng  done  by  this  machine. 

Another  factor  that  enters  into  the  rapid  work  done  by  one 
of  these  drills  is  its  tremendous  back-pull  or  stroke,  making  the 
drill  work  itself  loose  in  a  bad  hole  and  preventing  it  becoming 
"  stuck."  Even  when  the  steel  binds,  there  is  a  pull  and 
push  on  the  piston,  at  full  power,  for  every  revolution  of  the 
pulsator;  and  this  works  it  loose  almost  instantly.  Mr.  John 
states  that  the  wear  and  tear  on  these  drills  has  been  xery 
light. 

The  method  of  moving  the  pulsator  and  motor  in  the  quarry 
was  very  simple.  These  two  are  mounted  on  a  common  bed, 
which  has  two  sets  of  wheels  under  it.  A  cheap  wooden  frame 
for  a  track  was  made  in  sections,  for  the  truck  to  run  on.  Only 
a  few  of  these  sections  were  needed,  and  they  were  light,  inex- 
pensive and  easily  handled.  Small  steel  rails  can  also  be  made 
up  in  sections  and  used  in  the  same  manner,  and  naturally  they 


294      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

will  give  better  service,  as  well  as  allow  of  a  better  joint  being 
made  between  the  sections.  When  a  good  hard  bottom  occurs 
in  the  mine  or  quarry,  the  pulsator  and  motor  can  be  moved 
from  place  to  place  without  any  track,  the  wheels  running 
directly  on  the  rock.  On  tracks  it  can  be  carried  over  rough 
ground  or  muck  piles  with  the  aid  of  blocks  and  tackle. — Engi- 
neering and  Contracting. 


APPENDIX   K 


ROCK    DRILL    BITS 


The  success  of  almost  every  drilling  operation  depends 
on  the  selection  and  treatment  of  the  bits.  Too  much  attention 
cannot  be  given  this  important  part  of  the  work.  If  the  bits 
have  been  properly  formed,  sharpened,  and  tempered  for  the 
work,  and  if  they  are  changed  just  as  soon  as  their  edges  and 
gages  are  worn,  the  result  will  be  found  to  be  most  economical. 
The  power  drill  sharpener  has  removed  many  of  the  short- 
comings attendant  upon  the  hand-sharpening  process,  with 
the  result  that  where  these  machines  are  used  it  is  possible  to 
accomplish  from  25  to  100  per  cent  more  drilling  than  under 
the  old  methods.  The  reasons  for  this  are  that  the  power 
sharpener  turns  out  a  much  better  bit.  The  saving  in  the 
blacksmith's  wages  should  be  a  secondary  consideration.  The 
superior  quality  of  the  bits  made  in  a  machine  will  increase  the 
capacity  of  the  drilling  machines  sufficiently  to  pay  handsome 
dividends  on  the  cost  of  the  power  sharpener. 

For  the  guidance  of  those  unfamiliar  with  the  forms  of 
drill-bits  used  in  the  different  sections,  I  have  prepared  a  few 
drawings  of  those  in  use.  Fig.  i  represents  the  square  cross- 
bit  adopted  as  the  standard  for  American  mining  practice. 
It  is  made  from  either  round,  octagon,  or  cruciform  steel.  In 
the  copper  mines  of  ]Michigan  it  is  usually  made  of  a  round 
steel.  In  the  iron  mines  of  Michigan  and  Minnesota  and 
wherever  this  form  of  bit  is  used  east  of  the  Rocky  ^Mountains, 
octagon  steel  is  preferred;  but  in  the  Rocky  Mountain  and  Pacilic 
States  cruciform  steel  is  used.  The  reason  for  the  adoption 
of  this  form  of  bit  as  a  standard  will  be  appreciated  when  the 

295 


296 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


three  requirements  of  a  rock-drill  bit  are  recalled.  These  are 
"  to  chisel  out  a  hole  in  the  rock,"  "  to  keep  this  hole  round  and 
free  from  rifles,"  and  "  to  mud  freely."  There  is  really  a 
fourth  requirement,  which  is  "  to  do  as  much  drilling  as  pos- 
sible before  being  re-sharpened." 

The  different  kinds  of  rock  to  be  drilled  affect  the  wear  of 
the  bit.  Very  hard  rock  will  blunt  the  chisel  and  reaming 
edges.  The  softer  rocks  do  not  blunt  these  edges,  but  wear  the 
outer  sides  so  that  it  loses  its  gage  and  size,  still  appearing 
to  be  quite  sharp.     For  this  reason  a  bit  that  is  made  with  a 


Fig.  1 


Fig.  a 


Fig.  3 


Fig.  4 


Fig.  5 


square  edge  and  a  clearance  angle  of  8  degrees  will  drill  about 
four  times  as  long  in  soft  rock  as  a  bit  with  round  edges  and  a 
clearance  angle  of  i6  degrees,  before  being  reduced  to  the  size 
of  the  next  bit  that  is  to  follow.  Referring  to  Fig.  i  and  Fig.  2, 
the  latter  being  a  round- edge  bit  with  a  clearance  angle  of 
16  degrees,  it  will  be  seen  that  in  Fig.  i,  the  corners  of  the  bit 
at  the  base  of  the  bevel  describe  a  circle  that  is  equal  to  the 
circle  that  the  chisel  edges  describe.  This  is  as  it  should  be, 
as  it  is  impossible  for  the  chisel  edge  to  cut  out  all  of  the  rock. 
The  reaming  edge,  which  is  that  part  of  the  bit  extending  from 
the  chisel  edge  to  the  base  of  the  bevel,  marked  "  A  "  in  both 
Fig.  I  and  Fig.  2,  must  ream  the  outer  edge  of  the  hole  and  keep 


APPENDIX   K  297 

it  round  and  free  from  rifles.  In  Fig.  2  it  will  be  noted  that  the 
circle  described  by  the  corners  of  the  bit  at  the  base  of  the  bevel 
is  much  smaller  than  the  circle  described  by  the  chisel  edges. 
This  causes  an  excess  of  wear  on  the  corners  of  the  chisel  edges, 
the  bit  rapidly  loses  its  gage,  as  well  as  its  efficiency,  and  it 
is  almost  impossible  to  keep  the  hole  round.  Rifles  form  and 
these  cause  the  rotation  parts  of  the  drilling  machine  to  break, 
often  resulting  in  the  loss  of  the  hole. 

The  angle  of  the  bevel  of  the  face  of  the  bit  has  to  do  with 
its  Hfe,  as  well  as  with  the  property  of  "  mudding  "  freely. 
It  is  generally  accepted  that  if  this  angle  be  90  degrees  it  gives 
strength  and  permits  the  bit  to  ''  mud  "  or  throw  back  the 
cuttings  from  the  face  of  the  bit  when  the  drill  is  pointed  down- 
ward. Bits  made  like  Fig.  19  and  Fig.  20  will  not  "  mud  " 
freely.  Another  reason  why  bits  such  as  shown  in  Fig.  i 
are  preferable  to  those  illustrated  by  Fig.  2,  is  that  having  a 
long  wing  they  are  stronger  and  will  not  break  so  readily  as 
does  a  short  bit. 

The~Simmons  bit,  used  at  the  Champion  mine  at  Beacon, 
Mich.,  is  shown  in  Fig.  3.  In  it  two  of  the  wings  are  devoted 
entirely  to  reaming  and  keeping  the  hole  round  and  free  from 
rifles.  Some  tests  made  several  years  ago  in  jasper,  the  hardest 
rock  found  in  the  Champion  mine,  using  a  2f-inch  Rand  drill 
with  60-pound  air  pressure  at  the  compressor,  showed  an  average 
speed  per  minute  of  0.28  inches  for  the  ordinary  cross-bit,  and 
0.659  inches  for  the  Simmons  bit.  Both  forms  were  hand- 
sharpened. 

The  Brunton  bit,  the  invention  of  the  well-known  mining 
engineer,  D.  W.  Brunton,  is  extensively  used  in  Idaho  and 
Montana.  It  is  show^n  in  Fig.  4.  The  object  of  this  bit  is  to 
obtain  the  advantages  of  the  X-bit  without  the  attendant  dif- 
ficulties of  resharpening.  With  this  bit,  as  in  the  case  of  the 
X-bit,  the  piston  must  revolve  a  half  turn  before  the  cutting 
edges  will  strike  in  the  same  place  a  second  time.  It  is  as  easily 
resharpened  as  the  regular  square  cross-bit.  The  X-bit  itself 
is  shown  in  Fig.  5.  Since  the  invention  of  power-drill  sharpen- 
ing machines,  this  bit  is  fast  disappearing.     The  reason  will  be 


298 


SUBWAYS  AND  TUNNELS   OF  NEW  YORK 


understood  when  a  comparison  is  made  with  the  regular  square 
cross-bit  as  made  with  the  power-sharpener,  and  the  cross- 
bits  as  they  are  resharpened  by  hand,  shown  in  Fig.  i8.  Fig.  19 
and  Fig.  20.  The  X-bit  is  designed  to  prevent  rifles.  This 
the  hand-sharpened  cross-bit  would  not  do,  but  the  machine- 
sharpened  cross-bit  effectually  accomphshes.  Fig.  6  shows 
what  is  commonly  termed  the  high-center  bit.  This  was  for 
many  years  accepted  as  the  proper  form.  It  is  still  used  in  the 
mines  of  Cornwall  and  where  Cornish  customs  prevail.  Since 
the  introduction  of  hammer  drills  this  bit  is  again  finding  favor. 


Fig.  6 


Fig. 


Fig.  9 


Fig.  10 


It  is  of  especial  advantage  in  starting  a  hole,  the  high  center 
immediately  making  an  impression  on  the  rock,  whereas  the 
square-faced  bit  requires  a  flat  face  for  ready  starting.  For 
a  starting  bit  in  hammer  machines  it  has  no  equal.  Here, 
however,  its  advantages  over  the  square  bit  end.  Used  as  a 
bit  to  follow  the  starter,  it  is  liable  to  follow  slips  and  seams 
in  the  rock,  causing  crooked  holes,  which  are  sometimes  lost 
before  being  finished.  This  the  square  bit  will  not  do.  Fig. 
7  shows  a  bit  where  the  corners  are  in  advance  of  the  center. 
This  is  a  fast  cutting  bit.  The  corners  break  up  the  rock  in 
advance  of  the  center,  and  leave  Httle  for  the  center  to  do;  this 
causes  the  corners  to  wear  fast,  but  still  not  to  excess  when  it 


APPENDIX  K  299 

is  considered  that  they  do  most  of  the  work.  This  drill  will 
not  follow  slips  and  scams,  will  drill  a  round  hole,  and  is  easy 
on  the  drilling  machine.  The  weak  point  of  this  form  is  that 
the  leverage  is  so  great  on  the  corners  that  they  are  liable  to 
break  off  if  tempered  too  hard.  Fig.  8  shows  the  round-edge 
bit,  which  is  a  favorite  with  some.  In  soft  rock  this  is  good, 
but  in  hard  rock  it  permits  rifles  to  form  in  the  hole  because 
there  are  no  reaming  edges. 

The  Y-bit  shown  in  Fig.  9  gives  the  advantage  of  plenty 
of  room  for  the  cuttings  to  escape.  It  is,  however,  quite  diffi- 
cult to  make  and  resharpen  by  hand.  With  the  power-sharpener 
it  can  be  made  as  easily  as  any  other  form.  Fig.  10  shows  the 
"  bull  "  bit  in  use  in  the  lead  and  zinc  mines  of  the  Jophn, 
Mo.,  district  before  the  introduction  of  the  power-sharpener. 
The  extreme  hardness  of  the  limestone  and  flint  in  the  sheet- 
ground  of  that  district  caused  the  ordinary  cross-bit  as  made 
by  hand  to  wear  too  fast.  This  dull  bull-bit,  therefore,  had  to  be 
adoptetd.  Drilling  here  was  not  a  matter  of  cutting  the  rock, 
but  of  shattering  it  by  impact.  The  power-sharpener  has 
changed  all  this,  and  the  American  standard  cross-bit  as  made 
in  these  machines  is  now  used.  As  a  result  the  capacity  of  the 
drills  has  been  materially  increased.  In  mines  where  hand- 
sharpening  is  still  done  the  bull-bit  is  yet  in  use.  Fig.  11 
shows  the  Z-bit  used  in  hand-sharpening  in  the  southeast  Mis- 
souri lead  district.  This  bit  is  also  used  quite  extensively  in 
Germany.  In  both  places,  however,  the  advantage  of  the 
standard  square  cross-bit  as  made  with  the  power-sharpener 
is  fast  causing  it  to  be  displaced.  Fig.  12  shows  the  "  six- 
wing  rosette  "  bit  as  made  in  the  power-sharpener  in  use  at  the 
Penarroya  mines  of  Spain.  It  is  used  in  hammer  drills  only. 
Of  all  the  rosette  forms  of  bits,  this  has  been  found  to  be  the 
most  satisfactory.  Fig.  13  shows  the  square  cross-bits  when 
made  up  for  hammer  drills  where  a  hole  for  the  introduction 
of  air  or  water  to  remove  the  cuttings  apexes  at  a  point  back 
from  the  bevel  of  the  bit  in  one  of  the  recesses  between  the 
wings.  Fig.  14  shows  the  same  form  where  the  hole  ends  in 
the  center  of  the  cross  of  the  cutting  edges.     This  form  of  bit 


300 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


is  extensively  used.  Its  faults  are  that  a  core  is  formed  by  this 
hole;  this  core  fills  the  hole,  and  causes  a  stoppage  of  air  or 
water.  These  cores  have  been  known  to  become  as  much  as 
8  inches  long,  and  are  quite  difficult  to  remove.  To  clear  them 
away  the  core  must  be  burned  out  by  heating  the  steel  the 


Fig.  11 


Fig.  12 


Fig.  13 


Fig.  U 


Fig.  15 


full  length  of  the  core  in  a  slow  fire — a  sometimes  slow  and  tedious 
process.  This  difficulty  is  entirely  overcome  by  the  use  of  the 
bit  shown  in  Fig.  13.  The  Z-bit,  Fig.  15,  is  extensively  used  in 
Germany.  In  hammer  drilling  machines,  the  steel  is  formed 
in  bars  having  a  Z-shape.     While  I  show  this  bar  straight, 


Fig.  16 


Fig.  17 


Fig.  19 


Fig.  20 


it  is  usually  twisted  to  form  a  spiral.  It  is  an  easy  matter  to 
form  a  Z-bit  on  the  end  of  such  a  bar.  The  results  obtained 
are  excellent.  Holes  to  a  depth  of  16  feet  horizontal  have  been 
drilled  with  this  form  of  steel.  The  spiral  draws  out  the  cuttings 
much  the  same  as  an  auger.     Fig.  16  to  Fig.  20  are  given  to 


APPENDIX   K 


301 


show  the  evolution  of  the  cross-bit  where  hand-sharpening  is 
employed.  There  are  two  systems  of  hand-sharpening.  One 
is  known  as  the  set-hammer  system.  In  it  the  steel  is  hammered 
by  placing  a  set-hammer  on  the  bevels  and  driving  the  steel 
back.  The  results  of  this  method  are  illustrated  in  Fig.  i6  to 
Fig.  19.  Fig.  16  shows  a  bit  made  by  cutting  the  bevels  with  a 
chisel,  and  is  as  it  should  be  in  form.  Fig.  17  shows  this  bit 
after  about  the  third  sharpening.  Fig.  18  is  the  same  bit  after 
about  the  sixth  sharpening,  and  Fig.  19,  is  the  same  bit  at 
about  the  time  that  the  original  cross  that  was  formed  on  the 
bar  of  octagon  steel  has  become  exhausted.  The  other  sys- 
tem of  hand-sharpening  is  known  as  the  fuller  and  dollie  system. 
By  this  system  the  stock  is  first  drawn  sharp  at  the  corners,  as 


p'5 

1^/ 

K 

Fig.  21 


Fig.  23 


Fi^ 


Fig.  25 


shown  in  Fig.  20,  with  the  fuller,  after  which  it  should  be  set 
back  in  the  center  with  the  dollie.  Unfortunately  the  man 
swinging  the  sledge  hammer  gets  tired  before  the  bit  is  set  back 
enough;  the  result  is  that  the  bit,  partly  finished,  is  left  as 
shown  in  Fig.  20.  It  is  because  the  power-sharpener  has  the 
staying  power,  and  because  it  readily  finishes  a  bit  perfectly, 
that  inferior  bits  like  these  are  not  to  be  found  where  machine 
sharpening  is  employed. 

After  a  bit  has  been  forged,  it  should  be  properly  tempered, 
as  in  Fig.  21.  Fig.  22  shows  the  result  of  the  common  method 
of  tempering.  The  center  of  the  bit  is  soft,  while  the  corners 
are  hard.  When  the  bit  is  immersed  in  the  water  about  an  inch 
the  large  mass  of  metal  in  the  center  cools  more  slowly  than  the 
corners,  since  the  corners  have  three  sides  exposed  to  the  water. 


302 


SUBWAYS  AND   TUNNELS  OF  NEW  YORK 


Perhaps  the  center  had  not  chilled  at  all  when  the  bit  is  with- 
drawn for  annealing,  and  the  final  result  is  a  soft-center  bit, 
which  will  flatten  and  retard  the  work  of  drilling.  Fig.  23 
and  Fig  24  show  the  result  of  trying  to  temper  the  bit  with  the 
forging  heat,  by  plunging  the  whole  bit  into  the  water  as  soon  as 
it  is  sharpened.  The  line  of  tension  induced  by  cooling  is  indi- 
cated. At  this  place  the  drill  will  break.  Fig.  25  shows  the 
checking  caused  by  first  chilling  the  steel  back  of  the  bit  and 
then  plunging  with  the  forging  heat. 

For  the  purpose  of  tempering  as  shown  in  Fig.  21,  a  tank 
should  be  provided,  such  as  is  shown  in  section  in  Fig.  26.     This 


fl 


^^ 


S?>^>>i^'g»?»>-^->->~>~>->->-^^^^;5?^?j*^ 


Fig.  26. 


should  be  about  12  inches  deep  by  12  inches  wide,  and  of  suf- 
ficient length  to  accommodate  whatever  number  of  drills  are  to 
be  sharpened  in  a  day  with  the  machine.  The  water  inlet 
should  be  at  the  bottom,  and  the  outlet  should  be  placed  about 
three-quarters  of  an  inch  above  a  grate,  which  itself  should  be 
about  8  inches  above  the  bottom.  This  permits  the  bit  to  be 
immersed  to  a  depth  of  about  three-quarters  of  an  inch.  With 
a  tempering  tank  of  this  construction  the  bit  can  be  hardened 
to  any  desired  degree.  This  depends  on  the  temperature  of 
the  bit  when  placed  on  the  grate.  It  is  essential  that  the  drill 
stand  in  a  vertical  position.  To  lean  either  way  would  cause 
it  to  harden  to  a  greater  depth  on  one  side  than  on  the  other. 


APPENDIX  K 


303 


a 
< 


304  SUBWAYS  AND  TUXXELS  OF  XEW  YORK 

causing  a  tension  that  might  lead  to  breaking  of  the  wings.  It 
is  best  to  provide  a  rail  around  the  tank  about  the  distance 
required  to  hold  the  shortest  drill,  and  to  drive  pins  about 
3  inches  apart  in  this  rail.  By  placing  the  drills  between  these 
pegs  they  can  be  kept  in  a  vertical  position.  When  using  this 
tank  a  small  flow  sufficient  to  displace  the  water  heated  by  the 
cooling  of  the  bits  should  be  turned  on  to  keep  the  supply  always 
cool.     T.  H.  Proske,  in  Mining  and  Scientific  Press. 

Cost  of  Sharpening  by  Hand  at  the  Homestake  Mine,  as  Made 
up  in  the  Office  of  that  Company. 

Blacksmiths.  Helpers. 

Highland 2  $7.00  2  $6.00 

400  level I  350  I  3  •  00 

600  level 4  14.00  4  12.00 

700  level 3  10.50  3  9.00 


$35.00                  $30.00     $65.00 
120  drills  to  the  man  and  helper. 
1,200  pounds  of  black  coal 7 .  20 


'2. 20 


Cost  of  Sharpening  with  Machine,  at  the  Homestake  Mine. 

$72.00 

1  machine,  air  to  run  same $2 .  00 

2  blacksmiths,  $7.00;    2  helpers,  $6.00 .    13.00 

2  blacksmiths  sharpening  block  hole  steel 7 .  00 

2  extra  tool  packers 6 .  00 

720  pounds  coke 4.75 

Fire  brick  to  repair  furnace 20 


$32.95     32.95 


Saving  per  day $39 .  25 

1,000  drills,  2  shifts,  10  hours  each. 

Machine-sharpened  drills  last  better  than  those  sharpened 
by  hand  and  do  not  break  as  many  bits,  so  there  is  a  saving  of 
steel. 


APPENDIX  K  305 

"  One  machine  is  sharpening  steels  for  one  hundred  drills 
with  less  waste  of  steel  and  only  about  one-tenth  the  number  of 
broken  bits  to  trim  that  there  were  when  hand-sharpening  was 
employed." 

Rock  Drill  Sharpening  Arrangements.  Drill  sharpening 
presents  a  department  of  mine  costs  to  which  no  attention  is 
given  by  stockholders,  and  only  a  moderate  degree  of  attention 
by  the  mining  companies.  An  important  step  was  taken 
several  years  ago  in  reducing  the  cost  in  this  department  by 
the  invention  of  the  mechanical  drill  sharpeners,  actuated  by 
compressed  air,  which  have  now  been  introduced  in  the  shops 
of  nearly  all  the  mining  companies;  but  aside  from  this  the  com- 
panies themselves  took  no  step  to  economize  along  this  line 
except  to  introduce  the  machines  and  thus  reduce  the  labor 
costs. 

A  radical  departure  is  now  being  introduced,  however,  at 
a  number  of  mines  that  will  bring  about  even  a  greater  saving 
than  was  secured  when  mechanical  drill  sharpeners  were  intro- 
duced. This  is  to  alter  the  system  of  handling  the  drills.  To 
show  the  comparison  of  the  new  system  with  the  old,  the  method 
formerly  employed  will  first  be  enumerated. 

The  drills  are  assembled  underground  by  the  drill  boys, 
loaded  on  skips  and  hoisted  to  the  surface.  The  ordinary  rock 
skips  are  generally  used  for  this  purpose,  and  at  times  the  long 
drills  create  a  factor  of  danger,  projecting  above  the  skip  bail 
and  occasionally  catching  in  the  walls  of  the  shaft. 

At  the  surface  the  drills  are  piled  out  upon  the  floor  by 
the  drill  boys,  generally  in  disorderly  heap,  which  at  times 
bends  the  steel  so  that  it  has  to  be  heated  and  straightened, 
thus  drawing  its  temper.  Some  of  the  companies  have  special 
skips,  with  compartments  in  which  the  steel  is  laid  in  an  orderly 
manner,  and  thus  the  danger  of  catching  and  bending  is  removed. 

The  drills  are  then  loaded  into  wagons,  in  most  cases,  and 
hauled  by  teams  to  the  drill  shop,  where  from  two  to  half  a  dozen 
drill  sharpening  machines  are  employed,  depending  on  the  size 
of  the  mine.  Each  team,  driver  and  helper  in  this  service  costs 
about  $5.50  per  day. 


306      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

After  the  drills  are  sharpened  they  are  returned  to  the  under- 
ground service  by  reversing  the  steps  already  described.  This 
method  requires  that  the  drills  be  handled  from  six  to  ten  times. 
Each  drilHng  machine  underground  requires  about  1500  pounds 
of  drills  every  twenty-four  hours,  and  the  cost  of  sharpening 
will  at  times  reach  67.50  per  day  to  keep  the  drills  of  one  machine 
sharpened. 

A  complete  change  in  this  system  is  now  being  devised, 
to  be  introduced  later.  There  is  being  installed  in  each  shaft 
house  a  drill  sharpening  shop,  consisting  of  a  fireproof  room, 
a  forge  and  a  drill  sharpening  machine,  with  the  few  other  nec- 
essary tools.  Two  drill  skips  will  be  provided  at  each  shaft, 
with  compartments  in  which  the  drills  will  be  kept  assorted  by 
lengths.  When  a  skip  load  of  drills  comes  to  the  surface  it  will 
be  detached  from  the  hoisting  cable  and  shunted  from  the  tracks 
of  the  skipway  into  the  sharpening  shop,  which  will  be  inside 
the  shaft  house  structure  and  not  20  feet  from  the  collar  of  the 
shaft. 

In  the  shop  will  be  an  empty  drill  skip;  and  as  each  drill 
is  taken  from  the  loaded  skip  and  sharpened  it  will  be  placed  in 
the  empty,  until  the  latter  is  full  and  ready  to  attach  to  the 
hoisting  cable  to  be  lowered  into  the  mine,  leaving  the  former 
loaded  skip  empty  and  ready  for  the  next  consignment. 

There  will  be  only  one  to  three  hours'  work  at  each  shaft, 
according  to  the  volume  of  rock,  and  the  sharpeners  and  helpers 
will  make  their  rounds  from  shaft  to  shaft  handhng  the  work. 
No  one  will  be  employed  in  the  service  except  the  drill  boys 
necessary  to  make  the  underground  distribution,  and  the  neces- 
sary sharpeners  and  helpers  on  the  surface. — Copper. 


APPENDIX  L 

EXPLOSIVES;    DAMPNESS   AND    DYNAMITE;    BLASTING    GELATIN; 
COST  OF   BLASTING   IN  OPEN   CUTS 

Selection  of  Explosives  for  Tunnel  Blasting.  The  selection 
of  explosives  for  tunnel  blasting  probably  requires  a  more  care- 
ful study  of  conditions  than  for  any  other  kind  of  excavating. 
Maximum  speed  in  driving  cannot  be  attained  unless  the  explosive 
best  adapted  to  the  work  is  used.  When  starting  a  tunnel  or 
drift,  it  is  a  good  plan  thoroughly  to  try  out  several  explosives 
which  are  distinctly  different  in  action  before  finally  adopting 
any  one  of  them.  The  results,  however,  from  this  preliminary 
trial  will  be  of  little  or  no  value,  unless  all  the  explosives  are 
used  under  exactly  the  same  conditions.  Care  must  be  taken 
to  see  that  no  change  occurs  in  the  character  of  the  rock,  number 
and  direction  of  the  bore  holes,  strength  of  the  detonator,  kind 
and  quantity  of  tamping,  amount  of  water  encountered,  method 
of  connecting  up  the  bore  holes  for  firing,  and  that  the  explosive 
is  always  thoroughly  thawed.  If  a  material  change  in  any 
of  these  conditions  occurs  as  the  work  progresses,  further  tests 
should  be  made  to  determine  whether  a  quicker  or  slower,  a 
stronger  or  weaker,  explosive  might  not  break  the  ground,  or 
bottom  the  bore  holes  better,  or  make  it  possible  to  bring  out 
the  cut  with  fewer  holes  or  deeper  ones.  The  speed  at  which 
rock  can  be  drilled  does  not  indicate  how  it  will  break,  and  not 
infrequently  that  which  can  be  easily  drilled  is  very  difiicult 
to  blast. 

High  explosives  suitable  for  tunnel  blasting  should  not 
give  off  objectional  fumes  on  detonation,  and  accordingly 
gelatin  dynamite,  blasting  gelatin  or  ammonia  dynamite  should 
always  be  selected.  Gelatin  dynamite  is  made  in  various 
grades  of  strength,  from   25   to  80  per  cent  inclusive.     It  is 

307 


308  SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

comparatively  slow  in  action,  the  higher  grades  being  little, 
if  any,  quicker  than  the  lower  ones.  Blasting  gelatin  is  manu- 
factured in  only  one  strength,  which  for  comparative  purposes 
may  be  said  to  be  loo  per  cent.  It  is  more  powerful  and  quicker 
acting  than  any  other  blasting  explosive.  It  should  be  used 
sparingly,  therefore,  until  the  maximum  safe  charge  has  been 
learned  from  experience.  Good  results  will  often  be  had  in 
hard  ground,  if  a  few  cartridges  of  blasting  gelatin  are  used  in 
the  point  of  the  bore  hole,  with  gelatin  dynamite  on  top.  When 
this  is  done,  it  is  best  to  put  the  detonator  in  one  of  the  car- 
tridges of  blasting  gelatin.  Ammonia  dynamite  is  made  from 
25  to  75  per  cent  strength.  All  grades  are  quicker  than  gelatin 
dynamites  and,  generally  speaking,  the  quickness  increases 
with  the  strength — that  is,  the  stronger  grades  are  quicker, 
and  the  lower  grades  of  these  three  high  explosives  offer  a  wide 
range  in  strength  and  quickness  to  select  from,  and  it  is  always 
possible,  after  a  few  trials,  to  find  an  explosive  exactly  suited 
to  the  conditions. 

Railroad  tunnels,  mine  tunnels  and  drifts,  highway  tunnels, 
and  irrigation  tunnels,  are  being  driven  daily  through  various 
kinds  of  "  ground."  Often  it  is  a  matter  of  first  importance  to 
finish  them  quickly,  and  consequently  details  in  regard  to 
methods  and  equipment  are  matter  of  general  interest.  Within 
the  past  few  months,  a  number  of  speed  records  in  tunnels  of 
different  sizes  have  been  made,  and  descriptions  of  them  have 
appeared  in  various  technical  magazines. 

In  Engineering-Contracting  of  Oct.  20,  1909,  Mr.  J.  B.  Lip- 
pincott,  assistant  chief  engineer  of  the  Los  Angeles  aqueduct, 
gave  an  interesting  account  of  the  driving  of  the  Red  Rock 
Tunnel  of  the  Los  Angeles  aqueduct  system.  In  August,  1909, 
this  tunnel,  which  is  9  feet  10  inches  by  10  feet  8j  inches  in 
section,  was  advanced  106 1.6  feet.  Mr.  Lippincott  states  that 
the  explosives  used  were  Du  Pont  40  per  cent  ammonia  dynamite 
and  blasting  powder. 

In  the  Engineering  News  of  Nov.  18,  1910,  the  Red  Rock 
Tunnel  is  again  referred  to,  and  details  are  also  given  by  Mr. 
C.  H.  Richards,  division  engineer,  in  regard  to  a  tunnel  on  the 


APPENDIX  L  309 

Little  Lake  Division  of  the  Los  Angeles  aqueduct.  The 
explosives  used  in  this  tunnel  were  Hercules  40  per  cent  and  60 
per  cent  gelatin  dynamite,  the  average  weight  of  explosives 
per  cubic  yard  of  rock,  place  measurement,  having  been  only 
3.3  pounds,  or  about  35  pounds  per  lineal  yard  of  tunnel,  almost 
10  by  10  feet  in  section. 

A  short  time  before,  accounts  were  given  in  several  mining 
magazines  of  a  record  driving  speed  made  in  the  Roosevelt 
drainage  tunnel  at  Cripple  Creek,  Colo.  The  explosives  used  in 
this  tunnel  were  40,  50  and  60  per  cent  Repauno  gelatin  dyna- 
mite and  Du  Pont  blasting  gelatin. 

A  very  interesting  description  of  the  Rondout  pressure 
tunnel  of  the  Catskill  Aqueduct,  written  by  Mr.  John  P.  Hogan^ 
assistant  engineer  of  the  New  York  City  Board  of  Water  Supply^ 
was  published  in  the  Jan.  i,  1910,  number  of  the  Engineering 
Record.  Very  rapid  progress  was  made  in  this  tunnel,  and  also 
in  the  Moodna  pressure  tunnel  of  the  same  system,  described 
in  the  Engineering  Record  of  June  4,  19 10.  The  explosive 
which  gave  best  results,  and  which  was  used  exclusively  in 
both  of  these  tunnels,  was  60  per  cent  forcite — a  gelatin  dyna- 
mite. 

Reference  to  a  paper  by  B.  H.  M.  Hewett  and  W.  L.  Brown, 
on  the  land  sections  of  the  Pennsylvania  Railroad  North  River 
tunnels,  pubHshed  in  Vol.  XXXVI  of  the  Proceedings  of  the 
American  Society  of  Civil  Engineers,  and  reprinted  in  part  in 
Engineering-Contracting  of  May  11,  1910,  shows  that  40  per 
cent  forcite  was  used  in  blasting  on  the  ^Manhattan  section, 
and  60  per  cent  forcite  on  the  Weehawken  section. 

The  records  of  many  other  tunnels  recently  constructed 
further  illustrate  how  many  kinds  and  strengths  of  explosives 
are  used  for  blasting  under  the  different  conditions  encoun- 
tered in  one  class  of  work. 

The  specific  cases  referred  to  above  were  all  connected 
with  large  and  important  contracts,  where  equipment  and 
methods  were  of  the  best;  and  several  of  these  tunnels  were 
driven  at  record  speed.  The  fact  that  so  many  different  explo- 
sives were  used  in  the  seven  tunnels  goes  to  show  that  care  was 


310 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


taken  to  use  the  explosive  which  was  best  adapted  to  the  con- 
ditions; and  it  is  not  unlikely  that  the  speed  of  driving  these 
tunnels  was  largely  due  to  the  attention  given  to  the  selection 
of  the  explosives. 

This  point  is  equally  important  when  driving  narrow  tun- 
nels and  drifts.  After  a  study  of  the  rock  in  a  cross-cut  3  feet 
6  inches  by  7  feet,  in  the  Calie  shaft  at  Cripple  Creek,  it  was 
decided  that  best  execution  would  be  given  by  a  40  per  cent 
gelatin  dynamite.  Repauno  40  per  cent  gelatin  was  accord- 
ingly adopted,  and  it  was  necessary  to  drill  fourteen  holes  as 
shown  in  Fig.  i,  from  3  feet  6  inches  to  4  feet  six  inches  deep 


SECTION  E-F 


SECTION  AB  AND  C-D 


Fig.  1. 


and  blast  them  with  about  35  pounds  of  40  per  cent  gelatin 
dynamite,  in  order  to  advance  the  tunnel  about  3  feet.  In 
an  attempt  to  increase  the  speed  of  driving,  and  to  reduce  the 
cost,  the  face  was  drilled  with  eleven  holes,  as  shown  in  Fig. 
2,  and  these  holes  were  loaded  with  Du  Pont  blasting  gelatin 
in  the  points,  and  Repauno  40  per  cent  gelatin  dynamite  on 
top.  In  this  method  of  loading  about  7  pounds  of  the  blasting 
gelatin  and  17  pounds  of  the  gelatin  dynamite  were  used,  making 
a  reduction  of  about  15  per  cent  in  the  cost  of  explosives,  and 
20  per  cent  in  the  amount  of  drilling,  while  the  tunnel  was  still 
advanced  fully  3  feet  each  shift.  Here  the  adoption  of  a  more 
suitable  explosive  for  the  work  resulted  in  a  great  reduction 


AITENDIX   J. 


311 


in  cost  instead  of  increase  in  speed.    Engineering  and  Contrad- 
itig,  July  27,  1 9 10. 

Dampness  and  Dynamite.  Dynamite  should  never  be 
stored  in  tunnels  nor  in  any  place  where  dampness  exists. 
Although  a  tunnel  may  seem  dry,  all  rock-in-place  contains 
from  3  to  8  per  cent  of  moisture,  which  is  continually  being 
brought  to  the  wall-surface  in  underground  workings  by  cap- 
illarity where  it  is  evaporated  unless,  for  want  of  ventilation, 
the  air  is  saturated.  Thus  the  rock  is  continually  contributing 
moisture,  which  is  greedily  absorbed  by  the  sodium  nitrate  in 
the  dynamite,  that  salt  being  highly  hygroscopic.     As  soon  as 


SECTION  E-F 


SECTION  A-B  AND  C-D 


Fk;.  2. 


the  sodium  nitrate  has  deliquesced— that  is,  melted  from  absorp- 
tion of  moisture— the  homogeneity  of  the  dynamite  becomes 
distributed,  and  the  "  dope  "  fails  to  retain  the  nitroglycerine, 
which  then  leaks  out.  The  watery  substance  often  seen  on 
cartridge-paper,  and  the  oily  stain  seen  in  dynamite  boxes,  is 
due  to  the  leaking  of  the  nitroglycerine.  A  cartridge  in  this 
condition  is  far  more  liable  to  accidental  explosion  than  sound 
dynamite,  and  it  is  perilous  and  uneconomical  in  use.  It  will 
not  develop  the  same  energy  as  good  dynamite;  it  is  likely  to 
burn  and  blow  out  instead  of  detonating  properly;  and  it  is  a 
frequent  cause  of  "  misfires,"  and  of  the  failure  of  a  charge  to 
explode  to  the  bottom  of  a  hole.     Mining  and  Scientific  Press. 


312      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

Blasting  Gelatin.  Blasting  gelatin  consists  of  about  92 
per  cent  nitroglycerine  and  about  8  per  cent  gun  cotton.  It 
is  the  most  powerful  explosive  manufactured,  not  excepting 
clear  nitroglycerine.  Because  of  its  high  detonating  power 
it  is  erroneously  supposed  to  be  more  dangerous  to  handle 
than  ordinary  grades  of  dynamite;  but,  owing  to  its  gelatinous 
composition,  it  is  no  more  sensitive  than  40  per  cent  H.  G. 
dynamite.  In  appearance  it  is  somewhat  similar  to  gelatin 
dynamite,  although  more  elastic  and  gelatinous.  It  is  rec- 
ommended for  use  when  a  much  more  powerful  agent  than  the 
60  per  cent  dynamite  is  desirable.  It  gave  exceptionally  good 
results  in  a  tunnel  driven  through  hard  granite  where  60  per 
cent  gelatin  dynamite  failed  to  break  out  ten-foot  holes  satis- 
factorily. 

The  blasting  gelatin  in  this  work  was  used  in  the  cut  hole: 
only,  and  then  only  made  up  about  one-third  of  the  charge, 
the  remainder  of  the  charge  being  of  60  per  cent  gelatin  dynamite, 
which  was  loaded  on  top  of  the  blasting  gelatin. 

Cost  of  Blasting  Rock  in  Open  Cuts.  In  tunnel  w^ork  more 
explosive  must  be  used  than  in  open  cut,  yet  the  amount  may 
be  estimated  more  closely  as  there  are  records  available  of  the 
quantities  used.  The  weight  of  explosive  used  in  tunneling,  per 
cubic  yard,  varies  from  3  to  10  pounds,  according  to  the  char- 
acter of  the  rock,  and  the  shape  and  size  of  the  tunnel.  In 
small  mining  tunnels,  or  adits,  and  in  tunnels  for  sewers,  the 
amount  of  explosive  used  will  be  much  greater  per  cubic  yard 
than  in  larger  tunnels. 

Some  wonderful  results  in  tunnel  driving  have  been  accom- 
phshed  during  the  past  decade  by  adopting  definite  methods 
of  drilling,  loading  and  firing  holes. 

The  following  data  of  the  cost  of  explosive  in  open  cuts  are 
from  Daniel  J.  Hauer,  in  The  Contractor. 

Example  I.  In  mountainous  sections  of  the  country  certain 
materials,  such  as  indurated  clay,  cemented  gravel  and  similar 
earths,  frequently  classed  as  hardpan,  cannot  be  plowed  and 
excavated  with  scrapers,  owing  to  the  steepness  of  the  cuts 
and  embankments.     So  the  excavation  is  made  with  carts  or 


APPENDIX   L  313 

small  cars  in  a  manner  similar  to  rock  work.  Such  was  the 
case  in  this  example.  The  material  was  indurated  clay,  with  a 
few  sandstone  boulders  in  it.  As  picking  was  very  expensive, 
the  cut  was  shot  with  black  powder,  and  a  small  amount  of 
40  per  cent  dynamite  was  used  to  spring  the  holes  and  break 
up  some  of  the  largest  boulders.  Under  the  specifications  the 
material  was  classified  as  24  per  cent  loose  rock  (there  being 
no  hardpan  classification)  and  76  per  cent  earth. 

The  price  paid  for  explosives  was  $1.20  per  keg  for  black 
powder,  FF  and  FFF  grade  being  used;  11 4  cents  per  pound 
for  40  per  cent  nitroglycerine  dynamite;  42  cents  per  100  feet 
for  double  tape  fuse;  75  cents  per  hundred  for  caps;  and  from 
4  to  7  cents  each  for  electrical  exploders,  according  to  their  length. 

The  cost  per  cubic  yard  for  explosives  for  this  piece  of 
excavation  was  2.5  cents,  there  being  used  .40  pound  of  black 
powder  for  each  cubic  yard  of  material  excavated.  The  work 
was  done  in  September  and  October,  good  weather  prevailing. 

Example  II.  This  was  a  large  cut  in  cemented  gravel,  with 
only  a  few  sandstone  boulders  in  it.  It  was  almost  impossible 
to  pick  the  material  until  it  was  shot.  ]Much  of  the  gravel  ran 
in  cobble  sizes.  The  material  was  harder  to  excavate  than  in 
Example  I.  About  two-thirds  of  the  cut  was  gravel  and  boul- 
ders, the  rest  being  earth.  The  work  was  done  during  the  months 
of  December,  January  and  February,  when  the  ground  was 
frozen. 

The  cut  was  excavated  in  a  manner  similar  to  the  previous 
example,  small  cars  being  used  instead  of  carts,  and  nitro- 
granular  was  used  to  shoot  the  material  instead  of  black  powder. 
Forty  per  cent  strength  of  nitro  powder  was  also  used  instead 
of  dynamite  for  springing  holes  and  breaking  large  boulders. 
The  price  paid  for  nitrogranular  was  nine  cents  per  pound, 
and  ten  and  one-half  cents  for  nitro  powder.  The  prices  of 
other  materials  were  the  same  as  in  the  previous  example. 

The  cost  of  explosive  per  cubic  yard  for  this  work  was  1.7 
cents,  while  .16  of  a  pound  was  used  per  unit.  This  is  a  low 
record.  The  costs  given  do  not  include  any  labor  nor  drilling, 
covering  only  the  blasting  materials. 


314  SUBWAYS  AND  TUNNELS   OF  NEW  YORK 

Example  III.  In  excavating  earth  with  steam  shovels,  even 
where  rock  does  not  occur,  it  is  well  to  do  light  blasting,  espe- 
cially when  the  cutting  is  deep.  Only  enough  explosive 
should  be  used  to  shake  the  ground  and  not  throw  it  down. 
Then  the  shovel  will  work  faster,  since  the  material  will  run 
to  it  as  it  digs,  and  time  will  not  be  lost  through  caving  of  the 
high  banks  on  the  shovel.  This  last  consideration  is  an  import- 
ant one,  as  much  time  is  lost  by  cave-ins,  and  in  addition  the 
shovel  is  frequently  injured,  and  men  are  often  crippled  or  killed. 

On  one  job  six  hundredths  of  a  pound  of  black  powder  was 
used  per  cubic  yard  of  material.  The  holes  were  drilled  to  grade 
and  sprung  with  light  charges  of  dynamite,  the  material  to  be 
excavated  being  "  averaged  earth."  The  price  of  black  powder 
was  $i.io  per  keg.  The  cost  per  cubic  yard  for  explosives  was 
0.33  cents.  It  was  found  that  this  shooting  was  too  light,  as 
the  material  was  not  shaken  up  enough  to  prevent  cave-ins, 
so  on  another  job  a  new  method  was  used.  The  holes,  sunk 
with  a  well  driller,  were  put  from  3  to  5  feet  below  grade,  and 
were  not  sprung.  With  these  holes  the  charges  were  increased 
to  two-tenths  of  a  pound  per  cubic  yard,  making  a  cost  of  0.9 
cents  per  cubic  yard.  The  material  was  a  little  harder,  but 
cave-ins  no  longer  occurred.  However,  the  cost  was  deemed 
excessive,  since,  with  the  drilling  and  labor  of  loading,  it 
amounted  to  about  1.5  cents  per  cubic  yard. 

Judson  powder,  or  contractors'  powder,  was  used  in  place 
of  black  powder,  with  the  result  that  only  six  hundredths  of  a 
pound  was  needed,  and  the  cost  per  cubic  yard  for  explosives 
was  0.48  cents.  Just  as  efficient  work  was  done,  thus  proving 
that  Judson  was  better  adapted  to  this  class  of  blasting.  The 
Judson  on  this  job  cost  seven  cents  per  pound. 

Example  IV.  The  material  in  this  cut  was  clay,  shale,  boul- 
ders and  sandstone  ledges,  being  classified  as  35  per  cent  earth, 
35  per  cent  loose  rock,  and  30  per  cent  solid  rock.  Black 
powder  at  $1.20  per  keg  was  used  for  blasting,  and  40  per  cent 
dynamite  at  iit  cents  per  pound  was  used  for  springing  and 
breaking  up  boulders;  0.46  pound  of  black  powder  was  used 
for  each  cubic  yard  of  material,  and  0.12  pound  of  dynamite, 


APPENDIX   L  315 

making  a  total  of  0.58  pound  and  a  cost  of  4.3  cents  per  cubic 
yard. 

Example  V.  The  material  in  this  case  was  very  similar  to 
the  above,  there  being  a  little  less  solid  rock.  Instead  of  black 
powder  for  the  heavy  blasting,  Judson  powder  at  7!  cents  per 
pound  was  used.  Each  cubic  yard  took  0.26  pound  of  Judson, 
and  only  0.04  pound  of  dynamite,  a  total  of  0.30  pound,  making 
a  cost  of  2.5  cents  per  cubic  yard.  These  two  examples  make 
an  interesting  comparison,  showing  that  the  Judson  gave  more 
economical  results,  since  the  slight  difference  in  the  amount 
of  solid  rock  would  not  account  for  the  great  variation  in  the 
amount  of  explosives  used  and  in  the  cost.  This  statement 
is  verified  by  the  next  record. 

Example  VI.  Here  all  the  material  was  solid  sandstone 
ledges,  there  being  three  times  as  much  solid  rock  as  in  Example 
IV.  As  black  powder  was  used  on  this  work,  an  easy  com- 
parison is  made.  In  all  0.70  pound  of  explosives  was  used, 
0.47  pound  being  black  powder  and  0.23  pound  dynamite.  The 
cost  was  five  cents  per  cubic  yard.  These  examples  show 
that  the  black  powder  loosens  the  material,  but  it  is  necessary 
to  use  a  large  amount  of  dynamite  to  break  up  the  material  so 
that  it  can  be  moved.  It  must  be  remembered  that  in  all  of  the 
cases  given  here,  except  the  steam  shovel  work,  the  material 
was  moved  by  hand,  either  with  dump  carts  or  small  cars. 

Example  VII.  This  example  and  the  following  one  are  given 
to  illustrate  how  expensive  work  can  be  made  by  the  wrong 
method  of  blasting.  As  a  rule,  in  excavating  rock  cuts,  the 
cut  is  breasted,  and  then  one  or  two  holes  are  exploded,  accord- 
ing to  the  material  or  the  width  of  the  cut.  This  method  gives 
a  free  face  for  the  explosives  to  work  upon,  thus  obtaining  from 
them  their  most  effective  power. 

In  these  two  examples  it  was  decided  to  drill  holes  along 
the  center  line  of  cuts  that  were  to  be  20  feet  wide  on  the  bottom 
and  to  explode  them  all  at  one  time.  The  material  was  a  solid 
sandstone,  occurring  in  ledges,  being  classed  entirely  as  solid 
rock.  In  order  to  charge  the  holes  sufficiently,  they  had  to  be 
sprung  excessively,  which  was  expensive  in  the  use  of  dynamite. 


316  SUBWAYS  AND  TUNNELS   OF  NEW  YORK 

Judson  was  used  to  charge  the  holes,  sunk  about  2  feet  below 
the  grade  of  the  cut. 

For  this  work  0.65  pound  of  Judson  was  used  per  cubic 
yard,  and  0.60  pound  of  dynamite,  making  a  total  of  1.25  pounds, 
and  a  cost  of  12.4  cents  per  cubic  yard. 

Example  VIII.  This  too  was  all  solid  sandstone,  shot  in 
the  same  manner  as  above.  A  total  of  1.89  pounds  of  explosives 
was  used,  being  0.89  pound  of  Judson  and  one  pound  of  dynamite. 
The  cost  per  cubic  yard  was  23  cents.  In  Example  VII.  the 
depth  of  the  cut  was  from  16  to  20  feet,  while  in  this  case 
the  cut  was  more  than  30  feet  in  depth.  In  the  first  case 
the  depth  was  not  too  great  to  have  worked  with  one  lift,  but 
the  30  feet  was  too  deep  for  one  lift,  especially  when  the  cut 
was  not  worked  to  a  breast.  The  result  of  this  method  of 
blasting  was  not  to  throw  down  any  material,  even  when  the 
large  blast  was  made,  and  the  entire  top  of  the  cuts  had  to  be 
quarried  off  with  dynamite,  since  they  were  ruptured  so  that 
it  was  not  possible  to  use  either  black  powder  or  Judson  to  break 
it  up.  The  bottom  of  the  cuts,  where  the  full  force  of  the 
Judson  was  felt,  was  broken  up  too  much,  as  much  of  the  rock 
was  pulverized.  If  these  cuts  had  been  worked  to  a  breast, 
the  results  would,  no  doubt,  have  been  as  satisfactory  as  those 
of  Example  V,  and  in  the  following. 

Example  IX.  This  was  all  sandstone,  being  classified  as 
88  per  cent  soHd  rock  and  1 2  per  cent  loose  rock.  The  work  was 
done  in  the  winter  time,  during  the  months  of  January,  February, 
March  and  early  April,  while  the  work  in  the  other  two  cases 
was  done  during  excellent  autumn  weather.  The  rock  was  well 
breasted  before  being  shot,  and  was  blasted  so  that  little  dyna- 
mite was  needed  to  break  up  the  boulders.  In  nearly  every 
case  it  was  not  permissible  to  waste  any  of  the  rock,  else  the  cuts 
could  have  been  blasted  more  heavily,  and  there  would  have  been 
less  boulder  breaking. 

Judson  powder  was  used  for  the  heavy  blasting,  taking  0.35 
pound  per  cubic  yard  and  0.17  pound  of  40  per  cent  dynamite, 
a  total  of  0.52  pound,  making  a  cost  of  five  cents  per  cubic  yard. 

Example  X.  A  similar  piece  of  sandstone  excavation  being 


APPENDIX   L  317 

classed  as  2  per  cent  earth,  15  per  cent  loose  rock  and  83  per 
cent  solid  rock  was  blasted  with  black  powder,  being  first 
breasted.  There  was  used  0.70  pound  of  black  powder  and 
0.50  pound  of  dynamite,  a  total  of  1.20  pounds.  The  cost  per 
cubic  yard  was  twelve  cents,  the  work  being  done  in  the  middle 
of  winter. 

Example  XL  This  was  another  case  of  bad  judgment  shown 
in  blasting.  The  cut  was  a  side  hill — one  of  solid  sandstone — 
with  the  rock  at  an  angle  of  about  45  degrees.  The  greatest 
depth  of  cut  was  not  over  8  or  9  feet.  After  shooting  off  the 
toe  of  the  rock,  holes  were  drilled  at  the  upper  slope  and  sprung. 
It  was  then  found  that  the  rock  was  very  hard,  so  that  the  holes 
did  not  chamber  readilv,  and  when  the  heavy  charges  for 
springing  opened  up  seams  and  cracks,  the  rock  settled  back 
into  its  old  position.  A  considerable  amount  of  dynamite  was 
wasted  in  springing.  The  foreman  was  directed  to  shoot  the 
holes  with  straight  dynamite  after  springing  only  twice,  but 
he  continued  springing,  and  besides  loaded  the  holes  with  black 
powder  and  dynamite.  The  black  powder  cost  $1.35  per  keg 
on  this  job,  and  the  dynamite  twelve  cents  per  pound.  When 
the  blast  was  made,  the  dynamite  did  all  the  work  that  was  done, 
and  the  powder  was  ignited  by  it.  burning  for  over  five  minutes 
after  the  rock  was  thrown  down. 

Two  different  explosives,  as  black  powder  and  dynamite, 
should  not  be  used  in  the  same  hole.  Dynamite  explodes  by 
detonation  and  black  powder  by  ignition,  so  the  former  will 
act  a  little  quicker  than  the  latter,  always  robbing  it  of  its  eft'ect. 
This  is  what  occurred  in  this  case,  and  the  black  powder  was  a 
total  loss.  These  holes  should  have  been  shot  with  dynamite 
alone. 

There  was  used  2.05  pounds  of  dynamite  to  each  cubic  yard, 
making  a  cost  of  27  cents  per  cubic  yard.  In  addition,  2 
pounds  of  black  powder  was  used  to  each  cubic  yard  at  a  cost 
of  10.8  cents,  making  a  total  of  4.05  pounds  of  explosives,  and  a 
total  cost  of  37.8  cents  per  cubic  yard.  To  an  experienced  man 
these  figures  reveal  incompetency. 

Example   XII.  This   was   solid   sandstone,   but   instead   of 


318      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

using  either  black  powder  or  Judson,  nitrogranular  was  used 
for  the  blast  and  nitro  powder  for  springing  the  holes  and  break- 
ing boulders.  The  granular  cost  9  cents  per  pound  and  the 
nitro  powder  lo^  cents. 

There  was  used  0.24  of  a  pound  of  nitrogranular  per  cubic 
yard  and  0.17  of  a  pound  of  nitro  powder,  a  total  of  0.41  of  a 
pound,  at  a  cost  of  3.5  cents  per  cubic  yard.  This,  by  com- 
parison with  the  other  examples  given,  shows  a  low  cost. 

Example  XIII.  This  was  a  sandstone  cliff  that  had  to  be 
thrown  down  a  mountain  side  into  a  river.  Nitrogranular 
was  used,  and  a  small  amount  of  nitro  powder  to  spring  the  holes. 
The  blasts  are  successful,  throwing  all  but  a  little  of  the  mate- 
rial into  the  river,  so  that  the  labor  of  drilling  and  loading  and 
the  cost  of  explosives  was  almost  the  entire  cost  of  excavation. 
More  explosives  were  used  in  this  case  than  in  Example  XII, 
since  in  that  cut  there  was  to  be  no  waste,  while  in  this  case  all 
the  material  was  to  be  wasted. 

There  was  used  0.31  pound  of  nitrogranular  and  0.02  pound 
of  nitro  powder,  a  total  of  0.33  pound,  at  a  cost  of  3.7  cents 
per  cubic  yard. 

One  lesson  clearly  indicated  from  these  examples  is  that 
Judson  powder  and  nitrogranular  save  money  in  blasting  as 
compared  with  black  powder. 

In  some  cases  money  is  saved  in  the  first  blast,  while  much 
dynamite  is  also  saved  in  breaking  up  boulders  and  in  pop- 
hohng  the  bottom  of  cuts. 

Another  lesson  is  that  rock  cuts  should  always  be  breasted 
up  before  being  shot,  especially  if  the  cuts  are  of  considerable 
depth,  otherwise  much  of  the  force  of  the  explosive  is  lost. 


APPENDIX   M 

PUMPS  FOR  SINKING  AND  TUNNELING;    SINKING  CAISSONS 

The  first  attempts  at  the  construction  of  hydraulic  machinery 
were  made  in  the  Greek  school  at  Alexandria  about  120  B.C., 
when  the  fountain  of  compression,  the  siphon  and  the  forc- 
ing pump  were  invented  by  Ctesibius  and  Hero;  and  though 
these  machines  were  operated  by  the  pressure  of  the  air,  yet 
their  inventors  had  no  distinct  notions  of  the  prehminary 
branches  of  pneumatic  science.  The  forcing  pump  was  prob- 
ably suggested  by  the  Egyptian  wheel  or  noria,  which  was  com- 
mon at  that  time,  and  which  was  a  kind  of  chain  pump,  con- 
sisting of  a  number  of  earthen  pots  carried  around  by  a  wheel. 
In  some  of  the  machines  the  pots  have  a  valve  in  the  bottom 
which  greatly  reduces  the  resistance  of  operation ;  this  probably 
was  the  fundamental  idea  which  led  to  the  invention  of  the 
forcing  pump. 

Till  the  seventeenth  century,  when  in  1647  Pascal  discovered 
the  pressure  of  the  atmosphere,  the  statement  that  "  Nature 
abhors  a  vacuum  "  was  accepted  as  good  and  sufficient  cause 
for  water  rising  into  the  vacuum  produced  by  a  pump.  In 
1 601  Giovanni  Batista  Delia  Ponta  describes  an  apparatus 
by  which  the  condensation  of  steam  in  a  closed  vessel  produces 
a  vacuum,  and  may  be  used  to  suck  up  water  from  a  lower  level. 
To  the  Marquis  of  Worcester  (1656)  appears  to  be  due  the 
credit  of  making  the  first  useful  steam  pump.  It  worked  prob- 
ably hke  Delia  Ponta's  model,  but  with  a  pair  of  displacement 
chambers  from  which  the  water  was  displaced  alternately. 
Thomas  Savery  obtained  a  patent  in  1698  for  a  pumping 
apparatus  on  the  same  principle. 

In  1690  Denis  Papin  suggested  that  the  condensation  of 
steam  should  be  employed  to  make  a  vacuum  under  a  piston 

319 


320      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

previously  raised  by  the  expansion  of  steam.  Papin's  was 
the  earliest  cylinder-and-piston  steam  engine,  and  was  after- 
ward given  practical  shape  in  the  atmospheric  engine  of  New- 
comen.  About  1711  Newcomen's  engine  began  to  be  intro- 
troduced  for  pumping  mines;  by  1725  these  engines  were  in 
common  use,  and  held  their  place  for  about  three-quarters  of 
a  century. 

In  1782  Watt  patented  a  double-action  system  of  pumping 
engines.  In  1781  Hornblower  invented  the  compound  engine; 
the  compound  engine  was  introduced  widely  by  Woolf  as  a 
pumping  engine  in  Cornish  mines.  But  here  it  met  a  strong 
competitor  in  the  high  pressure  single-cylinder  engine  of  Tre- 
vithick,  which  had  the  advantage  of  greater  simplicity  of  con- 
struction, and  Woolf's  engines  fell  into  comparative  disuse. 

The  tendency  of  advance  up  to  the  present  time  in  the  types 
of  pumping  engines  has  been  towards  greater  compactness 
and  simplicity  in  design.  This  in  a  very  marked  degree  has  been 
the  case  in  the  type  of  pump  now  employed  for  general  service, 
and   sinking  pumps   in   construction   or   mining   operations. 

The  development  or  evolution  of  the  type  of  pump  demanded 
by  the  conditions  of  modern  tunnel  construction  is  illustrated 
in  the  more  compact  and  simple  form  of  each  succeeding  design, 
from  the  massive  atmospheric  beam  engines  of  Newcomen, 
the  lighter  beam  engines  with  higher  steam  pressure  of  Tre- 
vithick  and  Watt,  the  rotative  or  fly-wheel  type  of  pumping 
engine,  the  duplex  or  double-cylinder  direct-acting  pump  of 
the  Worthington  type,  the  single-cyhnder  direct-acting  pump 
with  outside  valve  gear,  and  culminating  in  the  compact  sim- 
plicity of  the  Cameron  pump,  in  which  the  few  moving  parts 
are  within  the  valve  chest  or  cylinders  and  not  subject  to  injury 
or  derangement   through  extraneous  causes. 

Before  the  introduction  of  the  direct-acting  pump  in  tunnel- 
ing or  mining,  the  installation  of  the  pumping  plant  was  a  serious 
feature  of  the  work,  the  machinery  being  heavy  and  not  of  a 
form  that  was  readily  movable  from  place  to  place  as  the  driv- 
ing or  work  advanced.  The  installation  was  kept  at  a  fixed 
point,  and  involved  the  necessity  of  laying  out  and  performing 


APPENDIX  M 


321 


the  driving  in  such  a  manner  that  sufficient  grade  for  the 
proper  flow  of  water  through  the  drains  could  always  be  main- 
tained through  gravity  to  the  pumps. 

The  maintenance  of  grades  and  drainage  ditches  to  permit 
the  flow  of  water  to  the  pumps  entailed  the  expenditure  of 
much  time  and  money.     The  introduction  of  the  duplex  direct- 


"  Cameron"  Regular  Pattern  Piston  Pump. 

acting  pumps  and  the  smaller  fly-wheel  pumps  made  it  possible 
to  do  away,  to  a  great  extent,  with  drainage  ditches,  as  the 
pumps  could  be  moved  as  the  exigencies  of  the  work  might 
require  or  the  conditions  permit.  But  in  the  confined  space 
in  headings  or  drifts,  where  there  is  a  car  track  or  where  the 
excavated  or  other  material  is  being  hauled  through,  it  is 
usually  necessary  to  cut  out  or  widen  the  drift  to  provide  space 
for  placing  and  housing  pumps  of  this  type. 

It  is  most  important  that  all  pumps  having  outside  or  exposed 


322      SUBWAYS  AND  TUNNELS  UF  NEW  YORK 

moving  gear  of  any  sort  should  be  properly  and  securely  housed 
as  a  protection  against  derangement  of  the  gear  by  material 
falling  from  the  cars,  blasted  stone,  material  from  the  roof  or 
sides,  grit  or  sand  or  material  floating  up  in  the  case  of  floods. 
To  protect  the  exposed  moving  parts  of  the  pumps,  by  provid- 
ing proper  housing  and  cutting  out  the  side  of  the  drift  if  nec- 
essary to  give  the  required  width,  may  entail  considerable 
outlay;  but  the  susceptibility  of  the  gear  to  derangement  and 
the  essential  function  of  the  pumps  justify  every  means  for 
their  proper  maintenance.  The  neglect  of  these  precautionary 
measures  has  proven  a  costly  experience  to  many  engineers 
and  contractors.  The  majority,  if  not  all,  of  the  contractors 
for  building  the  cross-river  tubes  coming  into  New  York,  used 
the  Cameron  single-cylinder  direct-acting  pump  for  sinking 
and  general  service. 

The  peculiar  advantages  of  this  pump  are  that  it  has  no 
outside  gear  of  any  sort  that  may  be  deranged  and  put  the  pump 
out  of  service;  it  requires  no  housing  or  protection,  as  its  exposed 
parts  are  very  much  stronger  and  prove  a  better  protection 
against  injury  than  any  housing  that  would  be  likely  to  be  put 
over  it.  These  pumps  may  be  placed  between  the  car  track 
and  the  wall  without  widening  of  the  drift  or  heading,  or  may 
be  close  to  blasting  operations  without  risk  of  injury.  In 
the  event  of  flooding  or  being  drowned  out  the  pump  will  start 
up  no  matter  how  deeply  submerged,  when  the  air  pressure  is 
turned  on.  There  have  been  cases  where  this  pump  has  been 
covered  with  broken  rock  and  debris  for  weeks  without  interrupt- 
ing its  efificient  operation. 

Foundation  Problems  in  New  York  City.  C.  M.  Ripley. 
The  gigantic  increase  in  the  erection  of  skyscrapers  in  the 
"  Lower  Broadway  "  section  of  New  York  City  during  the  past 
few  years  has  been  made  in  the  face  of  grave  and  increasing 
engineering  difhculties.  A  study  of  the  laying  of  the  founda- 
tions for  the  Trust  Company  of  America  Building  (see  Fig.  i), 
in  the  financial  section  of  Wall  Street,  will  bring  out  forcibly: 
(i)  what  these  problems  are,  and  (2)  how  the  talent  of  engineer- 
ing contractors  has  been  developed.     Less  than  a  dozen  years 


APPENDIX  M 


323 


"  Cameron  "  Sinking  Pump. 


324  SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


Fig.  1. 


APPENDIX   M 


325 


ago  the  following  conditions  would  have  been  considered  insur- 
mountable obstacles,  making  impossible  the  construction  of  a 
twenty-five  story  building  on  this  site. 

As  shown  in  the  accompanying  plan  (Fig.  2)  this  building 
is  situated  between  the  present  United  States  Trust  Company 


Wall  St. 


*  '5- 

^  1: 


and  the  Mills  buildings.  Owing  to  the  prevailing  prices  of 
Wall  Street  real  estate,  every  inch  of  available  space  had  to  be 
utilized,  with  the  result  that  the  foundations  of  the  new  building 
practically  "  rub  elbows  "  on  either  side  with  those  of  the  old. 
It  is  not  generally  understood  that,  as  we  approach  the  south- 
em  end  of  Manhattan  Island,   the  bed-rock  slopes  off  lower 


326 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


and  lower  below  the  surface,  so  much  so  that  at  Wall  Street  it 
is  80  feet  below  the  curb  and  at  the  Battery  between  90  and  100 
feet  below.  It  might  be  mentioned  in  this  connection  that  the 
rock  appears  at  water  line  at  about  Fourteenth  Street,  and 
continues  rising  as  we  approach  upper  Manhattan,  so  that  in 
building  projects  in  this  latter  portion  of  the  city,  it  is  often 
necessary  to  blast  away  a  miniature  mountain  before  the  site 

is  even  down  to  street  level. 
It  is  due  to  this  character- 
istic of  New  York's  geological 
formation  that  the  excavation 
for  the  great  Pennsylvania 
Railroad  depot  has  so  often 
been  termed  a  veritable 
"  quarry."  In  these  cases 
the  foundations  are  suppHed 
by  nature. 

In  striking  contrast  to 
such  simple  foundation  prob- 
lems, we  have  the  case  in 
hand.  Foundations  have  to 
be  laid  to  bed-rock,  through 
about  80  feet  of  quicksand 
and  water-bearing  strata, 
which  is  already  heavily 
loaded  by  adjoining  ten-story 
buildings.  In  digging,  water 
and  soft  mud  are  encountered 
but  a  few  feet  below  the  street 
level,  and  were  this  soft  muck 
pumped  out  or  removed  by 
any  of  the  old-time  methods, 
more  of  this  fluid  material  would  enter  the  excavation  from 
either  side,  and  the  adjoining  structures  would  settle  and  later 
collapse.  The  Foundation  Company,  to  whom  was  entrusted 
the  responsibility  both  of  planning  and  doing  this  work,  solved 
these  problems  by  employing  the  pneumatic  caisson  process, 


Fig.  3. 


APPENDIX   M 


327 


in  conjunction  with  the  Moran  air  lock,  an  invention  of  their 
vice-president,  Mr.  Daniel  E.  Moran,  C.E. 

The  principle  of  the  air  lock  was  used  for  the  underpinning 
of  the  adjoining  buildings  as  well  as  for  the  main  part  of  the 
work.  Cut  No.  5  shows  how  work  was  begun  even  while  the 
old  building  was  being  wrecked.  Niches  about  5  feet  above 
the  cellar  floor,  and  5  feet  wide,  were  cut  in  the  walls  of  the  adjoin- 
ing buildings  with  Box  electric  and  Ingersoll-Sergeant  steam 
drills  at  intervals  of  about  every  6  to  9  feet.  These  were 
carried  downward    through  the  old  foundation,  and  through 


=D 


—=o 


SECTION  ^1 


F=0 


=fe 


=D 


SECTION  3 


the  sand  under  the  foundation  until  the  water  line  was  struck. 
Then  a  6-foot  length  of  riveted  steel  pipe,  36  inches  in  diameter, 
was  jacked  down  into  the  sand,  thereby  employing  the  weight 
of  the  building  in  constructing  the  new  underpinning.  A 
downward  opening  door  was  installed  at  the  top  of  this  length, 
a  second  length  was  bolted  to  the  first,  and  then  a  second  down- 
ward opening  door  was  installed,  completing  the  miniature 
air  lock.  As  shown  in  Fig.  5,  compressed  air  was  suppHed  to 
the  bottom  chamber  and  the  work  pushed  lower  and  lower 
through  quicksand  or  hard  pan,  as  successive  lengths  of  pipe 
were  bolted  to  the  top,  and  material  excavated.  When  rock 
was  reached  the  entire  cyhnder  was  filled  with  concrete,  the 


328 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


steel  pipe  remafined,  and  when  the  steel  beams  were  placed,  as 
shown  in  the  left  side  of  Fig.  5,  the  underpinning  at  that  point 
was  completed.  Twelve  of  these  concrete  cyhnders  support 
the  wall  of  the  Mills  Building,  and  eleven  that  of  the  United 


Fig.  5. 


States  Trust   Building,  as  shown  by  the  circles  in  the  shaded 
portion  of  Fig.  2. 

Twenty-seven  concrete  piers  constitute  the  foundation  work 
proper  under  the  Trust  Company  of  America  Building.  The 
remarkable  speed  with  which  these  piers  were  sunk  to  bed- 
rock was  made  possible  mainly  from  this  one  fact:   The  Moran 


APPENDIX  M  329 

air  lock  allows  the  material  excavated  in  caisson  to  be  hoisted 
to  the  open  air  in  one  continuous  haul,  being  handled  but  once 
in  transferring  from  bottom  caisson  up  to  the  dumping  place, 
generally  a  truck.  This  feat  was  never  possible  with  any  other 
equipment  until  Mr.  Moran  took  the  lead  and  perfected  his 
device  shown  in  Fig.  4. 

The  square  and  rectangular  spaces  shown  in  Fig.  2  give 
the  location  of  the  concrete  piers  on  the  site  of  the  Trust  Com- 
pany of  America  Building.  In  Fig.  6  is  shown  the  4-boom 
traveler  derrick,  which  is  equipped  with  four  double-drum 
Lidgerwood  hoisting  engines,  and  which  effectively  covered 
the  entire  area.  It  served  to  place  the  caissons  (one  of  which 
weighed  20  tons  and  was  14  by  31  by  8  feet  high)  at  their  proper 
location.  It  also  hoisted  men  and  material  in  and  out  of  the 
twenty-seven  working  chambers.  A  typical  caisson  or  work- 
ing chamber  is  shown  in  Fig.  3. 

Fig.  6  shows  the  IMoran  air  lock  in  place,  near  the  top  of 
the  picture.  The  man  stooping  down  on  the  ground  is  the 
gage  tender,  who  keeps  the  pressure  steady  for  the  con- 
venience of  the  men  in  the  working  chamber,  and  the  man  at  the 
air  lock  communicates  signals  between  the  excavators  and  the 
engineers. 

Having  a  general  knowledge  of  the  difficulties  and  of  the 
apparatus  to  be  used,  and  having  finished  the  description  of 
the  underpinning,  we  shall  take  up  the  method  employed  in 
sinking  the  twenty-seven  great  concrete  piers  through  this 
soft  soil  to  bed-rock  without  weakening  the  adjoining  founda- 
tions.    See  Fig.   6. 

After  the  wooden  caisson  proper  had  been  located  accurately, 
the  workmen  with  picks  and  shovels  excavated  inside  the  open 
topped  frame,  which  gradually  sank  of  its  own  weight.  When 
it  had  sunk  to  water  level,  which  was  but  4  to  5  feet  below  the 
street,  preparations  were  made  to  apply  the  compressed  air 
as  follows:  The  open  top  of  the  caisson  was  roofed  over  tem- 
porarily and  the  first  lo-foot  section  of  the  steel  collapsible 
working  shaft  was  joined  to  the  upper  part  of  the  caisson,  as 
shown  in  Fig.  3.     Section  after  section  was  added  and  then  a 


330 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


Moran  air  lock,  as  shown  in  Fig.  6.  Then  a  section  of  tem- 
porary wooden  cofferdam  was  built  and  fitted  to  the  outside 
of  the  caisson,  so  as  to  extend  its  sides  upward  several  feet. 
This  was  to  act  as  a  falsework  for  retaining  the  successive  thin 


iff 


i-A.^ 


Hard-Pau\ 


>^^^i^^^^^- 


-^v^^\^^^^■-^- 


%ST# 


'VT^^^^^^'^^iP^^T'^BfTsrT^'^OT^ST'CT^^^'fc^^'^^^g;^^ 


Fig.  6. 


layers  of  concrete  dumped  into  the  annular  space  inside  the 
cofferdam  and  on  the  roof  of  the  caisson  surrounding  the  work- 
ing shaft,  as  will  be  noticed  in  the  right  hand  side  of  section  in 
Fig.  6.  After  the  first  lo  feet  of  concrete  had  hardened,  a  second 
cofferdam  was  fitted  in  a  higher  position,  and  the  concreting 


APPENDIX  M  331 

continued,  the  first  cofferdam  being  later  removed  and  used  as 
the  third.  One  gang  of  men  and  one  mixer  could  move  from 
cofferdam  to  cofferdam,  applying  a  2-foot  layer  in  each,  so  that 
by  the  time  they  returned  to  the  first  one  it  was  hardened  enough 
to  receive  its  next  layer  without  distorting  the  sheeting;  so 
nearly  the  full  height  and  full  weight  of  the  finished  pier  was 
used  to  force  the  caisson  down  to  its  final  resting  place  on  bed- 
rock, as  rapidly  as  the  excavating  could  be  done  by  the  men 
inside.  Alpha  Portland  cement  was  used  on  this  job  in  a  i  to 
2 1  to  5  mixture . 

Referring  again  to  Fig.  3,  it  will  be  noticed  that  the  lower 
edges  of  the  caisson  sides  are  sharpened  to  form  the  "  cutting 
edge  "  of  the  caisson,  since  they  follow  the  level  of  the  excava- 
tion and  are  pressed  down  by  the  great  weight  above.  The 
contracting  firm  have  prepared  special  2 -ton  cast-iron  weights, 
which  can  be  piled  on  top  of  the  concrete  pier  to  further  sink 
it,  in  case  the  "  skin  friction  "  on  the  sides  is  too  great  for  the 
pier  to  sink  of  its  own  weight. 

During  this  process  three  eight-hour  shifts  of  the  laborers 
were  digging  out  material  in  the  caisson  under  a  pressure  of 
from  18  to  24  pounds  per  square  inch.  This  material  was 
shoveled  into  buckets  and  hoisted  up  through  the  working  shaft 
and  the  air  lock  out  to  the  atmosphere,  all  in  one  continuous 
lift. 

When  bed-rock  is  reached,  it  is  leveled  off  and,  still  under 
compressed  air,  the  concrete  is  lowered  into  the  caisson  and 
rammed  in  place.  The  entire  caisson  is  filled  to  the  top,  the 
temporary  roof  removed,  and  as  the  men  retreat  up  the  tube 
they  unbolt  and  remove  a  section  of  the  collapsible  tubing  and 
hoist  it  up  for  use  in  sinking  another  caisson.  Gradually  the 
entire  space,  previously  used  as  a  passage  for  men  and  material 
in  and  out  of  the  working  chamber  or  caisson,  is  filled  with  con- 
crete, thus  making  the  pier  one  solid  monoHth  of  concrete  from 
bed-rock  to  the  column  base.  This  is  shown  on  the  left  side  of 
Fig.  6. 

Referring  again  to  plan  view.  Fig.  2,  it  is  seen  that  these  piers 
are  sunk  end  to  end  with  only  a  twelve-inch  space  between,  and 


332 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


that  the  chain  of  piers  around  the  entire  site  is  made  perfect 
by  welding  or  bonding  between  the  ends  of  each  pier.  This 
keeps  the  water  from  the  surrounding  soil  from  entering  either 
the  basement  or  sub-basement  of  the  building.  The  method 
is  as  follows:  In  Fig.  7  will  be  seen  the  end  faces  of  the  two 
adjacent  piers.  The  semi-octagonal  groove  shown  in  the  faces 
was  formed  at  the  same  time  that  the  coffer-dam  was  put 
around  the  top  of  the  caisson.  The  wooden  falsework  served  as 
a  "  core,"  displacing  the  concrete  from  top  to  bottom  of  each  end 
face  of  the  piers.  As  soon  as  two  adjacent  caissons  were  ready 
to  be  welded  or  bonded  the  space  bounded  by  ABAB  was 
excavated.    At  the  same  time  the  laborers  would  tear  off  the 


Fig.  7. 


boards  AA,  saw  them  into  the  shorter  lengths  BB,  and  nail 
them  in  position  BB,  as  shown  in  dotted  hnes.  The  space 
between  the  piers  thus  had  become  octagonal  in  shape,  and  was 
carried  down  the  few  feet  to  the  water  level.  The  planks  ABC 
were  removed.  A  4-foot  length  of  steel  cylinder  30  inches  in 
diameter  was  placed  in  the  opening,  and  the  space  between  it 
and  the  surrounding  concrete  and  boards  BB  was  filled  in  with 
concrete  and  made  air  tight.  An  air  lock  was  bolted  to  the 
top  of  this  cylinder  and  the  workmen  excavated  the  material 
between  A  and  B,  tearing  out  all  the  lumber  as  they  went  down, 
and  hoisdng  all  the  material  to  the  surface  except  what  was 
needed  for  complering  the  boards  BB  down  to  the  top  of  the 
caisson.  This  octagonal  well  was  then  filled  to  the  top  with 
concrete  under  pressure,  and  the  bond  was  complete.     When 


APPENDIX  M 


333 


these  connections  between  piers  were  completed  on  the  north, 
east  and  west  borders  of  the  building  site,  it  was  only  necessary 
to  make  the  bond  with  the  foundation  piers  of  the  Wall  Street 
Exchange  building  on  the  south  (put  in  by  the  same  contractor 


^r^ 


Fk;.  S. 

to  bed-rock)  in  order  to  fully  enclose  the  lot  and  prevent  future 
flooding  of  the  cellars,  which  reach  to  a  depth  of  nearly  40  feet 
below  the  water  level.  It  will  be  seen  from  Fig.  2  that  this 
was  done  without  expense  of  sinking  a  separate  line  of  caissons 
on  that  side. 


334 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


Another  advantage  in  this  solid  wall  type  of  bonded  founda- 
tion construction  is  that  the  piers  in  the  center  of  the  lot  can 
generally  be  sunk  without  the  expense  of  the  compressed 
air  method,  for  there  is  little  danger  of  any  water  seeping 
in  from  the  outside,  and  therefore  of  weakening  the  other 
buildings. 

At  this  stage  of  the  job,  the  cellars  can  be  safely  dug,  during 
which  work  the  shoring  of  the  neighboring  building  walls  is 
done,  as  shown  in  Fig.   8.     Fig.   9  illustrates  the  appearance 


Fig.  9. 


when  all  the  substructure  is  completed  and  the  cellar  made 
ready  for  installing  engines  and  boilers.  The  general  class  of 
work  of  which  this  job  is  merely  one  branch  is  civil  engineering 
in  W'ater  or  water-bearing  strata,  including  mine  shafts  in  wet 
or  marshy  lands,  bridge  piers,  sea  walls  and  tunnels.  Com- 
pressed Air  Magazine. 

Pneumatic  Bridge  Caissons  in  Great  Britain.     In  a  recent 
paper  before  the  Institution  of  Engineers  and  Shipbuilders  in 


APPENDIX  M  335 

Scotland,  Mr.  Andrew  S.  Biggart  described  the  operations  in 
construction  of  a  number  of  large  bridges  in  Great  Britain, 
in  each  of  which  undertakings  the  pneumatic  caisson  was  a 
prominent  feature,  the  work  all  executed  by  the  firm  of  Sir 
William  Arrol  &  Co.  (Limited),  Glasgow. 

The  Clyde  Bridge  of  the  Caledonian  Railway  Company  has 
five  deck  spans  from  60  to  200  feet  long,  carrying  at  one  end 
nine  tracks  and  at  the  other  end  thirteen  tracks.  Each  of  the 
river  piers  has  five  cylindrical  columns  seated  on  brick  piers, 
with  rectangular  pneumatic  caisson  foundations.  The  caissons 
are  of  steel  and  each  of  them  had  three  3i-foot  air  shafts  and 
was  built  on  a  falsework  extending  across  the  river,  which  also 
provided  for  the  delivery  and  storage  of  materials  and  for  the 
subsequent  erection  of  the  superstructure.  Two  wooden  trestle 
bents  were  erected  on  the  falsework  on  opposite  sides  of  each 
caisson,  and  each  pair  supported  a  pair  of  horizontal  riveted  steel 
plate  girders  forming  gallows  frames  over  the  caissons.  Four 
vertical  rods,  one  near  each  corner  of  the  caisson,  were  connected 
to  the  caisson,  and,  passing  between  the  pair  of  girders,  engaged 
saddles  commanded  by  hydraulic  jacks.  The  caisson  was 
lowered  by  the  jacks  to  water  level,  concreted  and  again  lowered 
and  released  from  the  suspending  rods  and  concreted  until  it 
took  bearing  on  the  river  bed.  During  this  operation  the  caisson 
was  maintained  in  horizontal  position  by  guys,  but  rose  and  fell 
with  the  tide. 

The  bridge  over  the  River  Barrow,  in  the  south  of  Ireland, 
has  thirteen  140-foot  fixed  spans  and  one  215-foot  swing  span 
with  15  piers,  each  made  with  two  8-foot  cylinders  26  feet  apart 
on  centers  which  had  their  bases  extended  to  a  diameter  of 
from  10  to  15  feet.  The  lower  portions  of  the  cylinders  were 
made  with  steel  rings  up  to  about  the  bottom  of  the  river,  and 
above  that  the  cylinders  were  made  with  cast-iron  rings.  The 
cyhnders  were  assembled  on  lateral  extensions  of  a  wooden 
falsework  platform  built  across  the  river;  the  working  chamber 
and  the  adjacent  cylinder  rings  were  lined  with  concrete  and 
lowered  to  the  river  bottom  by  hydraulic  jacks.  The  excava- 
tion in  them  was  partly  made  by  grabs,  but  in  every  case  was 


336      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

finished  under  pneumatic  pressure.  The  upper  rings  were  added, 
and  concreting  between  the  air  shaft  and  the  rings  was  continued 
as  the  cyhnders  sank.  Although  they  were  carried  down  to 
an  extreme  depth  of  120  feet  below  high  water  level,  the  pres- 
sure was  reduced  by  special  measures  to  a  maximum  of  45 
pounds  per  square  inch.  This  was  mainly  accomplished  by 
the  use  of  ejectors  operated  by  compressed  air  to  remove  the 
water  which  came  in  under  the  cutting  edge.  The  usual  pre- 
cautions were  taken  for  the  safety  of  the  workmen  by  reducing 
the  hours  of  work,  restricting  the  speed  of  their  exit,  and  pro- 
viding warm  refreshments  and  rest  for  them  immediately  after 
emerging  from  pressure.  After  the  working  chamber  was  con- 
creted the  air  pressure  was  maintained  on  it  for  several  days. 
The  top  ring  of  the  cylinder  was  made  of  special  depth  to  bring 
the  upper  edge  to  the  required  level.  The  cost  of  excavation 
at  the  maximum  depth  reached  $200.00  per  cubic  yard. 

The  Suir  Bridge,  near  the  Barrow  Bridge,  carries  the  same 
single  track  railway  on  nine  spans  of  about  140  feet,  with  cylin- 
der piers  similar  to  those  of  the  Barrow  Bridge,  but  not  sunk 
to  so  great  a  depth.  When  one  of  the  cylinders  had  sunk  to 
a  depth  of  70  feet  below  the  river  bottom,  and  was  subjected  to 
a  pressure  of  32  pounds,  one  of  the  cast-iron  rings  just  below  the 
bed  of  the  river  burst,  under  a  tensile  stress  of  about  1000  pounds 
per  square  inch.  The  casting  had  been  satisfactorily  tested 
before  acceptance,  and  pieces  of  it  were  tested  after  the  accident 
and  gave  results  up  to  the  specifications  without  disclosing  any 
flaw  in  the  metal.  No  explanation  has  been  ofTered  for  the 
break.  A  wooden  coft'erdam  was  built  around  the  top  of  the 
cylinder  and  pumped  out,  and  the  broken  ring  was  removed 
and  replaced  by  a  new  one,  and  a  concentric  steel  shaft  3  feet 
in  diameter  was  set  in  it  and  extended  down  through  the  con- 
crete lining  to  a  point  5  feet  below  the  upper  end  of  the  steel 
portion  of  the  cylinder.  The  lower  9  feet  of  this  shaft  was  then 
grouted  to  the  concrete  filling,  the  air-lock  was  placed  on  top 
of  it,  and  sinking  successfully  completed. 

The  Black  Friars  Bridge  over  the  Thames,  in  London,  has 
five  flat  steel  arch  spans  of  155  to  185  feet,  which  were  recently 


APPENDIX  M  337 

enlarged  by  extending  the  width  of  the  structure  from  43  to  73 
feet.  This  involved  a  corresponding  extension  of  30  feet  at  one 
end  of  all  the  piers,  which  were  of  masonry  and  were  each  sup- 
ported on  several  rectangular  pneumatic  caissons  and  one 
triangular  caisson  forming  a  cut-water  at  the  upstream  end, 
where  the  extension  was  made.  Pile  falsework  platforms  were 
made  enclosing  the  up-stream  ends  of  the  piers  and  extending 
10  feet  beyond  it  up-stream.  Steel  pneumatic  caissons  for  the 
foundations  of  the  pier  extensions,  with  a  semicircular  cut- 
water on  the  up-stream  end  and  a  recess  on  the  down-stream 
end  to  fit  the  nose  of  the  old  cut-water,  w-ere  assembled  and 
riveted  on  the  falsework.  The  downstream  end  of  the  caisson 
did  not,  however,  reach  entirely  to  the  main  part  of  the  old 
pier,  but  left  a  narrow  gap  there  on  each  side  of  the  down- 
stream end  of  the  old  cut-water.  The  caissons  were  assembled 
by  steel  stiff-leg  derricks  installed  on  the  falsework  platforms. 
A  timber  trestle  was  built  parallel  to  the  axis  of  the  caisson  on 
each  side  of  it  on  the  deck  of  the  falsework  platforms,  and  two 
pairs  of  steel-plate  girders  w'ere  seated  on  them,  one  at  each  end 
of  the  caissons,  provided  with  vertical  rods  and  hydrauhc  jacks 
by  which  the  caisson  was  slightly  lifted,  while  the  supports  under 
it  were  removed.  Concrete  was  filled  into  the  cutting  edge 
and  on  the  roof  of  the  caisson  and  it  was  lowered  to  the  bottom 
of  the  river,  the  sides  being  carried  up  by  a  temporary  steel 
cofferdam  continuous  with  them  and  heavily  braced  with  interior 
timbers  as  it  descended.  The  caissons  w^ere  sunk  just  below 
the  bottom  of  the  river  and  the  side  spaces  between  the  old 
and  new  caissons  were  enclosed  by  wooden  cofferdams  which 
were  pumped  out,  allowing  them  to  be  excavated  and  concreted. 
After  one  of  the  caissons  had  been  lowered  a  few  feet  below 
high  water,  and  was  still  suspended  from  the  overhead  girders, 
the  hydrauhc  jack  which  supported  one  of  its  corners  was  pre- 
maturely exhausted,  relieving  the  opposite  diagonal  jack  of  its 
load,  throwing  the  entire  250-ton  weight  of  the  caisson  on  the 
remaining  two  jacks,  and  settling  the  piles  under  one  of  them  a 
few  inches.  This  movement  caused  the  caisson  to  swing  and 
the  falsework  to  collapse,  precipitating  the  caisson  to  the  bottom 


338      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

of  the  river.  The  caisson  was  then  braced  by  interior  cross- 
girders  and  web  plate  brackets,  and  the  point  was  lifted  by 
hydraulic  jacks  operating  bars  suspended  from  two  box  girders 
braced  together  on  the  falsework  platform.  The  caisson  was 
then  moved  to  proper  position  on  sliding  bearings,  and  was 
sunk  in  the  usual  manner.     Compressed  A  ir  Magazine. 

Pit  Sinking  through  Frozen  Quicksand.  Mr.  E.  Seymour 
Wood  recently  read  a  paper  before  the  North  of  England  Institu- 
tion of  ]\Iining  Engineers  describing  a  remarkable  feat  of  shaft 
sinking  through  quicksand  b}'  the  aid  of  the  freezing  process. 
The  coal  mine  is  located  close  to  the  east  coast  of  the  county 
of   Durham,  which   lies   south   of  Newcastle-on-the-Tyne. 

The  difficulties  of  sinking  shafts  in  the  East  Durham  dis- 
trict arise  from  the  occurrence  of  magnesian  limestone  and 
underlying  yellow  sands,  the  latter  being  usually  found  as  a 
quicksand,  and  both  of  these  strata  contain  large  quantities 
of  water.  At  Dawdon,  the  magnesian  limestone  is  356  feet 
thick,  and  the  yellow  sand  92  feet  thick.  The  limestone,  as  is 
usual,  is  full  of  gullets,  giving  off  large  quantities  of  water.  Some 
of  these  gullets  are  connected  with  the  sea,  the  water  issuing 
from  them  being  salt.  The  question  was  therefore  con- 
sidered whether  to  erect  additional  pumping  plant  or  to  carry 
out  the  sinking  of  the  shafts  through  the  sands  in  a  frozen  state. 
It  was  decided  to  adopt  the  freezing  process.  Accordingly, 
the  shafts,  each  enclosed  in  a  wooden  shed,  were  handed  over 
to  the  contractors,  Messrs.  Gebhardt  and  Koenig,  Nordhausen, 
in  April,  1903.  This  firm  undertook  the  freezing  of  the  ground 
through  which  the  two  shafts  were  to  be  sunk,  and  also  the 
adjoining  ground,  to  such  an  extent  as  to  enable  the  owners 
of  the  coUiery  to  carry  out  their  sinking  arrangements  with- 
out the  aid  of  pumps,  until  each  shaft  was  sunk  to  a  depth  of 
484  feet  from  the  surface,  and  to  establish  and  maintain  a 
solid  wall  of  ice  around  each  shaft,  so  long  as  should  be  necessary 
for  the  purpose  of  sinking.  Twenty-eight  bore  holes  were  marked 
off  in  a  circle  30  feet  in  diameter  surrounding  the  shafts,  and 
were  bored  to  a  depth  of  484  feet.  After  the  whole  of  the 
freezing  tubes  were  inserted,  they  were  connected  to  the  inner 


APPENDIX  M  339 

and  outer  collectors,  for  the  circulation  of  brine.  The  length 
of  time  required  to  form  the  ice  wall  at  the  Castlereagh  shaft 
was  185  days.  The  ice  wall  was  maintained  353  days,  and  the 
total  time  of  freezing  was  538  days.  The  sand  .was  struck  at  a 
depth  of  371  feet  and  found  to  be  frozen  hard.  In  the  shaft 
bottom  the  frozen  sand  was  so  hard  that  blasting  had  to  be 
continued  throughout  the  deposits.  The  temperature  of  the 
frozen  sand  at  the  bottom  of  the  pit  was  i4°C.  (+6°  F.).  The 
thawing  of  the  frozen  ground  was  accomplished  by  circulating 
warm  brine  through  the  freezing  tubes.  Once  through  the 
frozen  sand  the  progress  of  the  operations  was  very  brisk. 
Compressed  A  ir  Magazine. 


APPENDIX   N 


ENGINEERING    DATA 


CUBIC  FEET  OF  FREE  AIR  REQUIRED  TO  RUN  ONE  DRILL  OF 
THE  SIZE  AND   AT  THE   PRESSURE   STATED    BELOW 


Size  and  Cylinder  Diameter  of 

Drill. 

A3S 

A3  2 

B 

C 

D 

D 

D 

E 

F 

F 

G 

H 

H9 

OS 

2" 

2i" 

2i" 

2f" 

3" 

3i" 

3iV" 

3i" 

3i" 

3f" 

4l" 

S" 

55" 

60 

SO 

60 

68 

82 

90 

95 

97 

100 

108 

113 

130 

150 

164 

70 

56 

68 

77 

93 

102 

108 

no 

"3 

124 

129 

147 

170 

181 

80 

63 

76 

86 

104 

114 

120 

123 

127 

131 

143 

164 

190 

207 

90 

70 

84 

95 

"5 

126 

133 

136 

141 

152 

159 

182 

210 

230 

100 

77 

92 

104 

126 

138 

146 

149 

154 

166 

174 

199 

240 

252 

340 


APPENDIX  N 


341 


3Aoqv 


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to 

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Tl-Tf'*'«l--^'i-'*VOVOVOVOVOVO 


totototototo'l-'t^"*'^'^^ 


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t^OO     OvO     1-1     tvj     ro-*-*vor^oo 

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to  ? 


342 


SUBWAYS  AND  TUNNELS   OF  NEW  YORK 


LOSS  OF  PRESSURE  IN  POUNDS   BY   FRICTION  IN  TRANS 

Initi.\l  Air  Pressure 


Delivery   in   Cubic   Feet   of 

9.84      14-73     19.64    24.60    29.4s   34-44  39-35    49-20    58.90     68.6    78.6     88.4      98.4 

o 

Equivalent    Delivery    i.n    Cubic 

50       75    :   100 

125 

150      175     200 

250 

300 

350 

400  1    450    ;    soo 

I 

18.24 
5.06 

1 

T  + 

11  .ZA  20.  16 

i-95i  4-33 
0.42I  0.0c 

7-79 
1.69 
0.52 
0. 19 
0.08 
0.04 

12.23 
2.65 
0.81 
0.30 
0.13 
0.07 
0.03 

17-53 
^.80 

2 

?     T7  6     77 

10.61 

3-24 
I.  22 

0.5s 
0.27 

0     T  S 

15.20 
4-65 
1.78 
0.78 

0  ^8 

2* 

3 

3i 

4 

4i 

5 

6 

0.13 
0.05 

0.29 
O.II 
0.05 

1. 16  1 .58  2.09 
0.440.590.78 
0. 19  0.  26  0.36 

0    00  0     1^0     T7 

6.31 
2-37 
1.07 

n    C2 

8.28 

3-II 
I  .40 
0.69 
0.    9 

0.  22 
0    08 

10.47 

3-94 

1.77 
0.88 
0.48 
0.28 

0     T  T 

'4^88 
2.20 
I     08 

0.05  0.07 
0  .  0  2  0    O/l 

0.  00 

0.  21  0. 29 

0.12   0     T  7 

0.  60 

0.06      0.08 

0  02     a  oz 

0.34 
0.  14 
0    06 

O.OI 

0.05 
0.02 

O.OI 

0.  06 

7 
8 

O.OI 

O.OI 

0.0^10.04!    0  oz 



0.  01   0.  OT 

0.02 
O.OI 

0.03 

O.OI 

9 

lO 

12 

14 

t6 



Initial  Air  Pressure 


Delivery  in    Cu 

Bic    Feet    of 

.2« 

7.74   1    H-3    1  15-2    1  19-4   1   23.2    |27.2|3l-o|  38-7    [46.5     1 54-2  1 62.0  1  69-7     1    77.4 

Equivalent    Delivery    in   Cubic 

50         75         100       I2S 

150 

I7S 

200 

250         300 

350 

1 
400      450       500 

I 

14-31 
3-96 
I -S3 
0-33 

O.IO 

0.03 

O.OI 

i\ 

8.46  15.31 

3.26    5.92 

H 

o.6d. 

13-79 

2-99 

■ 

2 

0.71      1.28      2.0Q 

A. 00  K.ZA 

8.32  12.01 

2-54    3  67 
0.96    1.38 
0.43    0.62 
0.21    0.30 
0.12    0  17 
0  07    0  00 

1 

2^ 

3 

3* 

4 

4* 

S 

6 

0.  21 
0.08 
0.03 
O.OI 

0-39 
0.14 
0.06 
0.03 
0.02 

"O.OI 

0.64 
0.24 

O.II 

0.05 
0.03 

O.OI 

0.91  1.25  1.63 
0.340.47  0.61 
0.150.21  0.27 
0.07  0. 100. 13 
0.04  0.06  0.07 
0.020  020  a  A 

4-99 
1.88 
0.84 
0.41 
0.23 

0      T  3 

6.53 
2-45 
I .  II 

0-54 
0   zo 

8-25 

3-13 
1.40 
0.69 
0    iS 

10.81 

3-83 

1-73 
0.85 

0.47 
0.27 
0. 10 

0.17    0.22 
0   oft     0   08 

.0.01 

O.OI 

O.OI 

0.02     0   03  n   n; 

7 
8 

O.OI     0   OT 

o.o2|0.03    0.04 

0    01   0    OT       0    OT 

0.05 
0  02 

9 
10 

0  01 

12 

14 
t6 

1 

For  longer  or  shorter  pipes  the  friction  loss  is  proportional  to  the  length,  ;.  c. 


APPENDIX  N 


343 


MISSION   OF   AIR   THROUGH    PIPES    1000    FEET    LONG. 
60  Pounds  Gage. 


Compressed   Air   Per   Minute. 


118.1137.5  156.6  176.S    196.4    294.S    393.7      492       589       686       786       884       984 


Feet  of  Free  Air   Per   Minute. 


600       700       800    ,    900        1000 


56  2 
871 
490 

19  O 
09  o 
04  o 
02  o 
01  o 


52 
29's 

12  2 

17  I 
67,0 

27  o 
120 
06  o 

030 

02  o 
o 


57  7 
75\3 
52  I 

87ii 
340 

150 
080 
04  o 
030 
01  o 


8.77 

4-33 
2.40 

1-37 
0-54 
o.  24 
o.  12! 
0.06 
0.04 
0.02 

O.OI 


1500      2000      2500      3000     3500 


4000     4500     5000 


965 
5-51 
2. 16 
0.98 
0.41 
o.  27 
o.  16 
0.06 

0.03 

O.OI 


07    o 


19 


I 

I* 

2 
2i 

3 

3i 

4 

4* 

5 

6 

7 


10,  8 
69  9 
99  10 
39  12 
18  14 
09  16 


80  Pounds  Gage. 


Compressed  Air  Per    Minute. 


92.9   108.2  124.0  139. 5     152        232        310       387        465        542        620       697        774     3v 

I ! a,j5 


Feet   of  Free   Air   Per    Minute. 


600     700    800    900     1000     1500     2000     2500     3000     3500     4000  '  4500  !  5000 


I 
li 

2 
2i 

3 

3* 

4 

4i 

S 

6 

7 


5. 61  7 
2.463, 
1.22  I , 
0.680, 
0.390, 
0.150, 
o .  06  o , 
0.030, 
0.02 

O.OI 


46:9 

374. 
662. 

92  I . 

530 

20  o. 
09  o. 

040. 

02  o. 
01  o. 


861. 

42I5 
182 
191 
69,0 

270 
120 
06  o 

03 

o 
o 


15-41 

7.62 

4.24 

2-43 
0-95 
0.43 


13.62  .  . 
7.5811. 
4.32I  6, 
1 .  69  2 . 
0.77  I. 
0.39  o. 
0.21  o. 
0.12  o. 
0.04  0.07  O.II 
0.02  0.03  0.05 
O.OI    O.OI    0.02 


72,13-25, 


5.27  6.78  8.54 

2-35    3-07    3-89 


1. 19 
0.65 

0.37  o 
0.15  o 
0.06    o 


0.85 

0.49 
19 
09 


1.97 
1.08 
0.66 
0.25 

O.II 


IO-S5 
4-79 

2 -.46, 
i-33| 

0.77! 

0.14; 


0.03    0.04    0.05    0.07I 


for  500  feet  one-half  of  the  above;  for  4000  feet  four  times  the  above,  etc. 


344 


SUBWAYS  AND  TUXXELS   OF  NEW  YORK 


LOSS  OF  PRESSURE  IN  POUNDS  BY  FRICTION  IN 

Initial  Air  Pressure 


D 

ELivERY  IN  Cubic  Feet  of 

6.41 

9.61 

12.81     IS. 81 

19.22 

22.39    25-62  31.62   38.44 

1 

44-78 

SI. 24   57.65 

63-24 

Equivalent  Delivery  in  Cubic 

50        75 

100  1    125 

ISO 

ITS 

200      250 

300 

350 

400       4S0 

500 

I 

11.89 
1.20 

t1 

"7-/19 

13.20 

S.II 

T  + 

1.28    2,87 
0.27    0.62 

7.71: 

11.42 

2.48 

0.76 
0.29 

0.13 

0.06 

0.03 

0.02 

O.OI 

t 

2 

I.I?    T.68 

3.36  4.43  6.72 

1.03    1.36    2.06 

0.39  0.51  0.77 
0.17  0.23  0.35 

o.09i  0.12    0.17 
0  04    0.06    0.09 
0.03    0.04    0.05 
O.OI    0.02    0.02 

9-95 
3.04 
1. 14 
0.51 
0.25 
0.14 
0.08 
0.03 

O.OI 

13-41 
4.II 

1-54 
0.69 

0.34 
0.19 

O.II 

0.04 
0.02 

O.OI 

2i 

3 

3i 

4 

4i 

S 

6 

0.08 
0.03 

O.OI 

0.19 
0.07 
0.03 

O.OI 

0.34 
0.12 
o.os 
0.02 

O.OI 

0.52 

0.19 

0.08 

0.04 
0.02 

5.40    6.85 
2.06     2.57 
0.92     1. 16 

0.45    0-57 
0.25    0.32 
0.15    0.18 
0.05    0.07 
0.03    0.03 
O.OI    0.02 
01 

8.21 

3.08 

1-39 
0.68 
0.38 
0.22 

O.OI 

0.08 

7 
R 

O.OI      O.OI 

0.04 
0.02 

9 
lo 

1 

1 

O.OI 

1 

14 
t6 

1 

, .  . . . 

i 

1 

* 

Initial  Air  Pressure 


Delivery  in  Cubic 

^EET    OF 

S.26      7.89      lO.si     13. IS    IS.79    18.41    21.05    26.30    31-S8    36.81 

42.10 

47.30 

52.60 

N    '^ 

Equivalent  Delivery  in  Cubic 

50    i    7S 

1           i 
100  '   125  I   150 

17s 

200         250         300         350 

400      450 

500 

9.88  22.20 
2.70    6.07 

39-50 
10  82 

1 

li 

2 

3 

4* 

5 

6 

7 
8 

9 
10 

12 

14 
16 

rf,  9.R  -^Ai-i 

33-05 

12.90 

2.78 

0.85 
0.32 

0.14 
0.07 

O.OJ. 

4.22    6.58    9.47 
0.91'   1.42    2.04 
0.28    0.43    0.63 
0.10    0.16    0.23 

0.05      0.07     O.II 

0.02    0.04   0.05 
O.OI    0.02    0.0? 

16.84  26.30 
3-63    5-68 
I. Ill   1.73 
0.42    0.65 
0.19    0.29 
0.09    0.15 
0.05    0.08 
0.03    0.05 

27.00  

1 

1.05 
0.23 
0.07 
0.03 

O.OI 

0.51 

0.16 
0.06 

0.03 

O.OI 

8.18  11.08 

2.51    3-39 
0.94    1.27 
0.42    0.58 
0.21    0.28 
0.12    0.16 

14-51 

4-44 
1.67 
0-75 
0.37 
0.21 
0.12 
0.05 
0.02 

O.OI 

18.38 
5-61 

2. II 

0-95 
0.47 
0.26 
0.15 
0.06 
0.03 
O.OI 
O.OI 

22.68 

6.95 

2.61 

1. 18 
0.58 

0.32 

O.OI 

0.02    0.02 

O.OI      O.OI 

0.07    0.00 

0.18 

O.OI    0.02    0.0^    0.04. 

0.07 

O.OI 

O.OI    0.02 

O.OI 

0.03 

0.02 

.  i  . 

1 

O.OI 

. 

; 



For  longer  or  shorter  pipes  the  friction  loss  is  proportional  to  the  length  —  i.e. 


APPENDIX    N 


345 


TRANSMISSION  OF  AIR  THROUGH  PIPES   1000  FEET  LONG 
loo  Pounds  Gage. 


Compressed  Air  per  M 

nute. 

76.88 

89.56'  102.5]  riS-3 

] 
I26.S  192.2 

256.2   316.2    384.4!  447-8  j  S12.4   576.5 

632.4 

II 

Feet  of  Free  Air  per  Minute. 

Nw 

600      700      800 

900 

1000    1500 

2000    2500 

3000    3500    4000 

4500  1  5000 

. 

1 

li 

li 

' 

1 

■ 

2* 

4.58 
2.14 
1.03 
0.57 
0.33 
0.12 
0.05 
0.03 
0.02 

O.OI 

6.10    8.1^ 

TO. 27 

T2.2n 

li 

4 
4l 
S 
6 

7 
8 

9 

10 
12 

2.79'  3.67    4.64[   5.60 
1.38    1. 81     2.29    2.76 
0.77    i.oo    i.27i   1.23 

O.dA     0.?7     0.76     0.88 

12.81 

6.68 

3-51 
2.03 
0.78 
0.36 
0.18 
0.09 
0.05 
0.02 

O.OI 

11-35 
6.61 
3-62 
1.41 
0.67 

0-33 
0.18 

O.IO 

0.04 
0.02 

O.OI 

9-56 

5-51 
2.14 
0.97 
0.49 
0.27 

0.16 
0.06 

14.04 

8.II 
3.16 

1-44 
0,76 

0-39 
0.23 
0.00 

10.95  14.48 
4.26    5.59 
1-93    2.55 
0.98    1.30 
0.53    0.72 
0.31    0.41 
0.12    0.16 

0.17     0.22 
0.07     O.IO 

0.04'  0.05 
0.02    0.03 
O.OI    0.02 

....      O.OI 

0.28:  0.34 
0.13    0.16 
0.06    0.08 
0.04    0.04 
0.02    0.03 

O.OI      O.OI 

i 

7.04 

3-22 
1.84 
0.89 
0.52 
0.2T 

8.51 

3-88 
1.98 
1.07 
0.63 

0.2t 

0.03    0.04 
O.OI    0.02 

0.05     0.07     0.09     O.II 

0.0?    0.04    o.o::    0.06 

14 
16 

^ 

•J 

125  Pounds  Gage. 


Compressed  Air  per  Minute. 

63.20 

73.70    84.20    94-70     105-1 

IS7-9    210.5 

1 
263.0!  315-8 

368.1   422.0  4730  526.0 

1       1       1 

Feet  of  Free  Air  per  Minute. 

M^ 

600      700      800      900 

1000 

1500 

2000 

2500    3000 

3500 

4000 

4500    5000 

I 

1                       I 

1 

Ti 

1 

jl 

2 

10.00  13.60 
3-76    5-II 
1.69    2.31 
0.84    I. 14 
0.46    0.63 
0.27    0.36 
O.IO    0.14 
0.05    0.06 
0.02;  0.03 
O.OI    0.02 

O.OI      O.OI 

17.80        .       1       . 

1 

2* 

6.68    8.45  10.42 
3.01    3.81    4.71 
1.49    1.88    2.32 
0.83    1.04    1.29 
0.47    0.60    0.74 
0.18    0.23    0.29 
0.08    O.II    0.13 
0.04    0.05    0.07 
0.02    0.03    0.04 
O.OI    0.02'  0.02 

O.OI      O.OI      O.OI 

1 

23.48 

10.  >o 

h 

4 

4l 
5 
6 

7 
8 

9 
10 
12 

tS.8t 

20.40  

5-23  9-30 
2.90  5.15 
1.65   2.94 
0.64   1. 15 
0.29    0.52 
0.15    0.26 
0.08    0.15 
0.05    0.08 
0.02    0.03 
O.OI    0.02 

14.52  20.90 

8.05 11.59 

4.60    6.63 

1.80  2.59 
0.82   1. 18 

0.41    0.60 

0.23  0.33 
0.13  0.19 

0.05    0.07 
0.02.  0.03 
O.OI    0.02 

28.51 
15-78 

9.01 

3-53 
1.61 
0.81 

0-45 
0.26 

O.IO 

20.61 

II.  0 

4.61 

2.19 

1.06 

0.58 
0.34 

O.I? 

26.10 
14.90 

5-83 
2.65 

1-34 
0.73 
0.43 
0.17 
0.08 
0.04 

32.20 

18.45 
7.20 

3-27 
1-65 
0.90 

0-53 
0.21 

O.IO 

0.05 

0.04    0.06 

14 

' 

O.OI 

0.02 

0.03 

16 

for  500  feet  one-half  of  the  above;   for  4000  feet  four  times  the  above,  etc. 


346 


SUBWAYS  AND   TUNNELS   OF  NEW  YORK 


HORSE-POWER  DEVELOPED  IN  COMPRESSING  ONE  CUBIC  FOOT 
OF  FREE  AIR  FROM  ATMOSPHERIC  PRESSURE  (14.7  POUNDS) 
TO  VARIOUS   GAGE   PRESSURES 

Initial  Temperature  of  the  Air  in  Each  Cylinder  Taken  as  60°    F 
(Jacket  Cooling  not  Considered). 


Gage     I  so 

Adiabatic  Compression. 

Pressure.   Com 

pression.    ^^^  g^^^^ 

Two  Stage. 

Three  Stage. 

Four  Stage. 

0332 

0358 

0623 
0842 

30 
40 
50 

"03^ 
0713 
0842 
0950 

1 

I187 

60 

70 

1042 
II22 

1331 
1465 

.128 

.122 

.119 

80 

1 194 

1585 

■137 

•131 

.127 

90 

1258 

1695 

.146 

•139 

•135 

100 

I317 

1800 

■154 

.146 

.142 

125 

1443 

2036 

.171 

.161 

•157 

150 

1549 

2244 

.186 

•174 

.  169 

2CX> 

1719 

2600 

.210 

.196 

.  190 

300 

1964 

3164 

•247 

.229 

.220 

400 

214I 

3613 

.276 

•253 

.242 

500 

2279 

3889 

.299 

.272 

.260 

600 

2393 

4318 

.318 

.288 

•275 

700 

2489 

.4608 

•335 

.302 

.289 

800 

2573 

■4873 

•349 

■314 

•299 

QOO 

.2649 

■  5114 

•363 

■325 

.310 

1000 

.2720 

•5337 

■375 

■335 

•  318 

1200 

.2829 

■5742 

•397 

•353 

■333 

1400 

.2924 

.6102 

.414 

.368 

•347 

1600 

.3012 

.6427 

•432 

.381 

•359 

1800 

.3087 

.6724 

•447 

•393 

•369 

2000 

•3154 

.7003 

.460 

•403 

•379 

Note.     The  above  values  are  for  sea-level  conditions  only. 

GLOBE  VALVES,  TEES,   AND   ELBOWS 
The  reduction  of  pressure  produced  by  globe  valves  is  the  same  as  that  caused 
by  the  following  additional  lengths  of  straight  pipe,  as  calculated  by  the  formula: 

1 14X diameter  of  pipe 


Additional  length  of  pipe= 


Diameter  of  pipe  \  j ij 

Additional  length   j     2 


I -h  (3. 6 -H  diameter) 
3       32         4         5 


6    inches 


7 
10 


13       16 


28 


36 

24 


feet 
inches 


44     53     7°     88     115     143     162     181     200    feet 
The  reduction  of  pressure  produced  by  elbows  and  tees  is  equal  to  two-thirds 
of  that  caused  by  globe  valves.     The  following  are  tne  additional  lengths  of  straight 
pipe  to  be  taken  into  account  for  elbows  and  tees.    For  globe  valves  multiply  by  |: 
Diameter  of  pipe    \    i     i|       2     2I         3       3?        4         5         6    inches 
Additional  length   ' 


2 

3 

5 

7 

9 

II 

13 

19 

24 

feet 

7 

8 

10 

12 

15 

18 

20 

22 

24 

inches 

30     35     47     59       77       96     108     120     134    feet 
These  additional  lengths  of  pipe  for  globe  valves,  elbows,  and  tees  must  be 
added  in  each  case  to  the  actual  length  of  straight  pipe.      Thus  a  6-inch  pipe, 
500  feet  long,  with  i  globe  valve,  2  elbows  and  3  tees,  would  be  equivalent  to  a 
straight  pipe   500  +  36-4- (2 X  24)-!- (3 X  24)  =  656  feet  long. 


APPENDIX  N 


347 


LOSS  OF  WORK  DUE  TO  HEAT  IN  COMPRESSING  AIR  FROM 
ATMOSPHERIC  PRESSURE  TO  VARIOUS  GAGE  PRESSURES  BY 
SIMPLE  AND   COMPOUND   COMPRESSION 

Air  in  Each  Cylinder;    Initial  Temperature  6o°  F. 


t 

One  Stage. 

Two  Stage. 

Three  Stage. 

Four  Stage. 

Percentage  of  Wor 

<  Lost  in  Terms  of 

pu, 

00 
CIS 

O 

Iso- 
thermal 
Com- 

Adia- 
batic 
Com- 

Iso- 
thermal 
Com- 

Adia- 
batic 
Com- 

Iso- 
thermal 
Com- 

Adia- 
batic 
Com- 

Iso- 
thermal 
Com- 

Adia- 

batic 
Com- 

pression. 

pression. 

pression. 

pression. 

pression. 

pression. 

pression. 

pression. 

6o 

29.9 

23.0 

134 

II. 8 

8.6 

7-9 

4-7 

4-5 

70 

30.6 

234 

14. I 

12.4 

8.7 

8.0 

6.1 

5.7 

80 

32.7 

24.6 

14 -7 

12.8 

9-7 

8.9 

6.4 

6.0 

90 

34-7 

25.8 

16. 1 

13-8 

10.5 

95 

7-3 

6.8 

100 

36.7 

26.8 

16.9 

14-5 

10.9 

9.8 

7.8 

7-3 

125 

41. 1 

29.2 

18.5 

15.6 

II. 6 

10.4 

8.8 

8.1 

150 

44.8 

30-9 

20.1 

16.7 

12.3 

10,9 

9.1 

8.4 

200 

51-2 

33-9 

22.  2 

18. 1 

14.0 

12.3 

10.5 

9-5 

300 

61.2 

37-9 

25-7 

20.5 

16.6 

14.2 

12.0 

10.7 

400 

68.7 

40.7 

28.9 

22.4 

18.2 

154 

131 

II-5 

500 

70.6 

41.4 

31.2 

23.8 

193 

16.2 

14. 1 

12.3 

600 

80.4 

44-5 

32.8 

24.7 

20.4 

16.9 

14.9 

130 

700 

85.0 

46.0 

34-6 

25-7 

21.3 

17.6 

16. 1 

13.8 

800 

895 

47.2 

35-7 

26.3 

22.0 

18. 1 

16.2 

13  9 

900 

93  0 

48.2 

371 

27.0 

22.6 

18.5 

16.6 

14.4 

1000 

96.1 

49  0 

37-9 

275 

23.2 

18.8 

16.9 

14-5 

1200 

102.8 

50-7 

40-3 

28.8 

24.8 

19.9 

17.7 

150 

1400 

108.6 

52.0 

41-5 

293 

259 

20.5 

18.6 

15-7 

1600 

II3-4 

53-1 

43-5 

303 

26.5 

20.9 

19.2 

16. 1 

1800 

II7-5 

54-0 

44-8 

310 

27-3 

21.2 

19.6 

16.4 

2000 

122.0 

550 

45-8 

31-4 

27-5 

21-5 

19.9 

16.5 

348 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


FLOW  OF  AIR  THROUGH  AN  ORIFICE, 

In  Cubic  Feet  of  Free  Air  per  Minute,  Flowing  from  a  Round  Hole  in 
Receiver  into  the  Atmosphere 


«-  ^.     rA 

<U  CJ  w 

Receiver  Gage  Pressure. 

Eo^ 

• 

0"=" 

2  lbs. 

5  lbs. 

10  lbs. 

15  lbs. 

20  lbs. 

25  lbs.  j  30  lbs.   35  lbs. 

40  lbs. 

A 

.038 

•0597 

.0842 

•103 

.119 

•133 

•156    .173 

.19 

^ 

■153 

.242 

•342 

.418 

4H5 

•54 

.6321   .71 

77 

iV 

647 

965 

1.36 

1.67 

I 

93 

2 

16 

2.52    2 . 80 

3 

07 

i 

2 

435 

3 

86 

5 

45 

6.65 

7 

7 

8 

6 

10.     II. 2 

12 

27 

4 

9 

74 

15 

40 

21 

8 

26.70 

30 

8 

34 

5 

40.     44.7 

49 

09 

i 

21 

95 

34 

60 

49 

60. 

69 

77 

00.    100.    IIO 

45 

i 

3Q 

00 

61 

60 

«7 

107. 

123 

i3« 

161.    179. 

196 

35 

61 

00 

96 

50 

136 

167. 

193 

216 

252.    280. 

306 

80 

1 
4 

«7 

60 

I. S3 

196 

240. 

277 

310 

362.    400. 

441 

79 

t 

IIQ 

50 

i8q 

267 

326. 

37« 

422 

493-    550- 

601 

32 

I 

150 

247 

350 

427. 

494 

550 

645-   :7i5- 

785 

40 

li 

242 

3«4 

543 

665. 

770 

860 

1000. 

i^ 

350 

550 

780 

960. 

2 

62s 

9«5 

1 

45  lbs. 

so  lbs. 

60  lbs.  1  70  lbs. 

80  lbs. 

90  lbs. 

100  lbs. 

125  lbs. 

64 

.208 

.225 

•  26     . 295 

■33 

■364 

.40 

.486 

^ 

«43 

.914 

1.05    I 

19 

1-33 

I 

47 

I. 61 

I 

97 

iV 

3 

36 

3  64 

4.2   i   4 

76 

532 

5 

«7 

6.45 

7 

85 

1 

8 

I.^ 

4 

14-50 

16.8   i  19 

0 

21 .2 

^3 

50 

25.8 

31 

4 

4 

S3 

8   58.2 

67.    1  76 

85- 

94 

103. 

125 

^ 

121 

130. 

151.    1171 

191. 

211. 

231. 

282 

^ 

215 

232. 

268.    '304 

340. 

376. 

412. 

502 

* 

S3b 

364- 

420.    I476 

532. 

5«7 

645- 

785 

4 

482 

522. 

604.    '685 

765. 

«43 

925- 

^ 

658 

710. 

622.    930 

1004. 

I   860 

930    1 

1 

DENSITY   OF   GASES  AND   VAPORS 

Air  at  Same  Temperature  and  Pressure  being  i.o;  also  Weight  of  a  Cubic 
Foot  at  62°  F.  Under  Atmospheric  Pressure  29.92  Inches  Mercury 


Density,  Air  | 

at  Same 
Temp,  and 
Pres.  being 

i.o(Regnault) 


Specific  Gravity 

or  Density,  Water 

at  62''  being  i.o. 


Weight  of  a 
Cubic  Foot 
in  Pounds. 


Cubic  Feet 

at  62°  in 
One  Pound. 


Air  (atmospheric) i .  00000 

Hydrogen  gas .06926 

Oxygen  gas i .  10563 

Nitrogen  gas 97i37 

Carbonic  acid  gas i  .52901 

Carbonic  oxide  gas 9674 

Vapor  of  water I         6235 

Vapor  of  alcohol i .  589 

Vapor  of  sulphuric  ether  2 .  586 
Vapor  of  oil  of  turpentine  4 .  760 
Vapor  of  mercury |     6.976 


.001221      or     sTa 

. 0000846  or    1 1 820 

.001350  or  yix 
.001185  or  sir 

.001870   or   6  35 

.00118   or  ^7 

.0007613  or  TSta 

.00194  or  5T5 
.00316  or  3T8 
.00581   or  17  2 

.  00850   or  jTa 


.07610 
.00527 
.08414 

•07383 
. 11636 

•07364 
■04745 
. 12002 
. 19680 
.36224 
•52987 


13-14 

189. 70 

11.88 

13  54 

8.59 

13.60 

21 .07 

8.27 

5.08 

2.76 


APPENDIX   X 


349 


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350  SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


Useful  Information — Steam 

A  cubic  inch  of  water  evaporated  under  atmospheric  pres- 
sure is  approximately  converted  into  one  cubic  foot  of  steam. 

The  horse-power  of  boilers,  as  per  standard  adopted  by 
the  A.  S.M.E.,  is  30  pounds  of  water  evaporated  per  hour  at  a 
pressure  of  70  pounds  per  square  inch  and  from  a  temperature 
of  100  degrees  Fahrenheit. 

Well  designed  boilers,  under  successful  operation,  will  evap- 
orate from  7  to  10  pounds  of  water  per  pound  of  first-class  coal. 

Each  square  foot  of  heating  surface  is  considered  sufficient 
to  evaporate  2  pounds  of  water;  therefore  with  an  engine  using 
30  pounds  of  water  per  horse-power  per  hour,  each  horse-power 
of  the  engine  requires  15  square  feet  heating  surface  in  the  boiler. 

On  I  square  foot  of  fire  grate  can  be  burned  on  an  average 
from  10  to  12  pounds  of  hard  coal,  or  18  to  20  pounds  of  soft 
coal,  per  hour,  with  natural  draft. 

Two  and  one-quarter  pounds  of  dry  wood  is  ec|ual  to  one 
pound  of  average  quality  soft  coal. 

Steam,  engines  consume  fron  12  to  50  pounds  of  feed  water, 
and  from  I3  to  7  pounds  of  coal,  per  hour  per  mdicated  horse- 
power. 

Condensing  engines  require  from  20  to  30  times  the  amount 
of  feed  water  for  condensing  purposes;  approximately  for  most 
engines,  i  to  I2  gallons  condensing  water  per  minute  per  indicated 
horse-power. 

Surface  condensers  for  compound  steam  engines  require 
about  2  square  feet  of  cooling  surface  per  horse-power;  ordi- 
nary engines  will  require  more  surface  according  to  their 
economy  in  the  use  of  steam.  It  is  absolutely  necessary  that 
the  air  pump  should  be  set  lower  than  the  condenser  for  satis- 
factory results. 

The  efTect  of  a  good  air  pum.p  and  condenser  should  be  to 
get  25  inches  of  vacuum  and  to  make  available  about  10  pounds 
more  mean  effective  pressure  with  the  same  terminal  pressure, 
or  to  give  the  same  mean  effective  pressure  with  a  correspond- 


APrENDIX   X  351 

ingly  less  terminal  pressure.  Approximately,  a  good  condenser 
will  save  one-fourth  of  the  fuel  consumed,  or,  in  other  words, 
increase  the  power  of  the  engine  one-fourth,  the  fuel  con- 
sumption remaining  the  same. 


Useful  Information — Water 

One  cubic  inch  weighs  .0361  pound. 

One  pound  equals  27.7  cubic  inches. 

One  cubic  foot  equals  62.4245  pounds  at  39  degrees  Fahren- 
heit;   7.48  U.  S.  gallons;    6.2321  imperial  gallons. 

One  U.  S.  gallon  equals  8.331 11  pounds;  231  cubic  inches; 
.13368  cubic  foot. 

One  imperial  gallon  equals  10  pounds  at  62  degrees  Fahren- 
heit; 277.274  cubic  inches;  .16046  cubic  feet. 

One  pound  pressure  equals  2.31  feet  in  height. 

One  foot  in  height  equals  .433  pound  pressure. 

Petroleum  weighs  62-  pounds  per  U.  S.  gallon,  42  gallons 
to  the  barrel. 

To  convert  imperial  gallons  into  U.  S.  gallons,  multiply 
by  the  factor  1.2.  To  convert  U.  S.  gallons  into  imperial  gal- 
lons multiply  by  the  factor  .8333. 

A  miner's  inch  is  a  measure  for  flow"  of  water,  and  is  the 
quantity  of  water  that  will  flow  in  one  minute  through  an  open- 
ing I  inch  square  in  a  plank  2  inches  thick  under  a  head  of  6^ 
inches  to  the  center  of  the  orifice.  This  is  equivalent  approx- 
imately to  1.53  cubic  feet,  or  11^  gallons  per  minute. 

To  find  the  diameter  of  pump  plungers  to  pump  a  given 
quantity  of  water  at  100  feet  piston  speed  per  minute,  divide 
the  number  of  gallons  by  4,  then  extract  the  square  root,  and  the 
result  will  be  the  diameter  in  inches  of  the  plungers. 

To  find  the  number  of  gallons  delivered  per  minute  by  a 
single  double-acting  pump  at  100  feet  piston  speed  per  minute, 
square  the  diameter  of  the  plungers,  then  multiply  by  4. 

To  find  the  horse-power  necessary  to  elevate  water  to  a 
given  height,  multiply  the  weight  of  the  water  elevated  per 


352      SUBWAYS  AND  TUNNELS  OF  NEW  YORK 

minute  by  the  height  in  feet  and  divide  the  product  by  33,000 
(an  allowance  should  be  made  for  water  friction  and  a  further 
allowance  for  losses  in  the  steam  cyHnder,  say,  from  20  to  30 
per  cent). 

The  mean  pressure  of  the  atmosphere  is  usually  estimated 
at  14.7  pounds  per  square  inch,  so  that  with  a  perfect  vacuum 
it  will  sustain  a  column  of  mercury  29.9  inches,  or  a  column 
of  water  33.9  feet  high  at  sea  level. 

To  determine  the  proportion  between  the  steam  and  pump 
cyHnder,  multiply  the  given  area  of  the  pump  cylinder  by  the 
resistance  on  the  pump  in  pounds  per  square  inch,  and  divide 
the  product  by  the  available  pressure  of  steam  in  pounds  per 
square  inch.  The  product  equals  the  area  of  the  steam  cyhnder. 
To  this  must  be  added  an  extra  area  to  overcome  the  friction, 
which  is  usually  taken  at  25  per  cent. 

The  resistance  of  friction  to  the  flow  of  water  through  pipes 
of  uniform  diameter  is  independent  of  the  pressure  and  increases 
directly  as  the  length  and  the  square  of  the  velocity  of  the  flow, 
and  inversely  as  the  diameter  of  the  pipe.  With  wooden  pipes 
the  friction  is  1.75  times  greater  than  in  metalhc.  Doubling 
the  diameter  increases  the  capacity  four  times. 

To  determine  the  velocity  in  feet  per  minute  necessary  to 
discharge  a  given  volume  of  water  in  a  given  time,  multiply  the 
number  of  cubic  feet  of  water  by  144  and  divide  the  product 
by  the  area  of  the  pipe  in  inches. 

To  determine  the  area  of  a  required  pipe,  the  volume  and 
velocity  of  water  being  given,  multiply  the  number  of  cubic 
feet  of  water  by  144  and  divide  the  product  by  the  velocity  in 
feet  per  minute.     Cameron  Steam  Pump  Works. 


APPENDIX  N 
PRESSURE  OF  WATER 


353 


The  pressure  of  water  in  pounds  per  sciuare  inch  for  every  foot  in  height  to 
260  feet;  and  then,  by  intervals,  to  3000  feet  head.  By  this  table,  from  the 
pounds  pressure  per  square  inch,  the  feet  head  is  readily  obtained,  and  vice  versa. 


-C 

J3 

^ 

j: 

ji 

j£ 

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(3 

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m 

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d 

5J 

(U 

X 

0   l_ 

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23-39 

fe 

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p^ 

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cu 

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P-, 

I 

0.43 

54 

107 

160 

69-311 

213 

92.20 

285 

123.45 

2 

0.86 

55 

23 

82 

108 

46 

78 

161 

69-74^ 

214 

92.69 

290 

125.62 

3 

1.30 

56 

24 

26 

109 

47 

21 

162 

70.17 

215 

93-13 

295 

127.78 

4 

1-73 

57 

24 

69 

no 

47 

64 

163 

70.61 

216 

93-56 

300 

129.95 

5 

2. 16 

58 

25 

12 

III 

48 

08 

164 

71.04 

217 

93-99 

305 

132.12 

6 

2-59 

59 

25 

55 

112 

48 

51 

165 

71-47 

218 

94-43 

310 

134.28 

7 

3  03 

60 

25 

99 

113 

48 

94 

166 

71.91 

219 

94.86 

315 

136.46 

8 

3  46 

61 

26 

42 

114 

49 

38 

167 

72.34 

220 

95-30 

320 

138.62 

9 

3  89 

62 

26 

85 

115 

49 

81 

168 

72.77 

221 

95-73 

325 

140-79 

10 

4-33 

63 

27 

29 

116 

50 

24 

169 

73-20 

222 

96.16 

330 

142-95 

II 

4.76 

64 

27 

72 

117 

50 

68 

170 

73-64 

223 

96.60 

335 

145.12 

12 

5-20 

65 

28 

15 

118 

51 

II 

171 

74-07 

224 

97-03 

340 

147-28 

13 

5-63 

66 

28 

58 

119 

51 

54 

172 

74-50 

225 

97-46 

345 

149-45 

14 

6.06 

67 

29 

02 

120 

51 

98 

173 

74-94 

226 

97-90 

350 

151-61 

15 

6.49 

68 

29 

45 

121 

52 

41 

174 

75-37 

227 

98.33 

355 

153-78 

16 

6.93 

69 

29 

88 

122 

52 

84 

175 

75-80 

228 

98.76 

360 

155-94 

17 

736 

70 

30 

32 

123 

53 

28 

176 

76.23 

229 

99.20 

365 

158.10 

18 

7-79 

71 

30 

75 

124 

53 

71 

177 

76.67 

230 

99-63 

370 

160.27 

19 

8.22 

72 

31 

18 

125 

54 

15 

178 

77-10 

231 

100.00 

375 

162.45 

20 

8.66 

73 

31 

62 

126 

54 

58 

179 

77-53 

232 

100.49 

380 

164.61 

21 

9.09 

74 

32 

05 

127 

55 

01 

180 

77-97 

233 

100.93 

385 

166.78 

22 

9-53 

75 

32 

.48 

128 

55 

44 

181 

78.40 

234 

101.36 

390 

168.94 

23 

9.96 

76 

32 

.92 

129 

55 

88 

182 

78.84 

235 

loi .70 

395 

171. II 

24 

10.39 

77 

33 

-35 

130 

56 

31 

183 

79-27 

236 

102.23 

400 

173-27 

25 

10.82 

78 

33 

.78 

131 

56 

74 

184 

79.70 

237 

102.66 

42s 

184. 10 

26 

11.26 

79 

34 

.21 

152 

57 

18 

185 

80.14 

238 

103.09 

450 

195.00 

27 

11.69 

80 

34 

-65 

133 

57 

61 

186 

80.57 

239 

103.53 

475 

205.77 

28 

12.12 

81 

35 

08 

134 

58 

04 

187 

81.00 

240 

103.96 

500 

216.58 

29 

12.55 

82 

35 

-52 

135 

58 

48 

188 

81.43 

241 

104.39 

525 

227.42 

30 

12.99 

83 

35 

95 

136 

58 

91 

189 

81.87 

242 

104.83 

550 

238.25 

31 

1342 

84 

36 

39 

137 

59 

34 

190 

82.30 

243 

105.26 

575 

249  -  09 

32 

13-86 

85 

36 

82 

138 

59 

77 

191 

82.73 

244 

105.69 

600 

259.90 

33 

14.29 

86 

37 

25 

139 

60 

21 

192 

83-17 

245 

106.13 

625 

270.73 

34 

14.72 

87 

37 

68 

140 

60 

64 

193 

83.60 

246 

106.56 

650 

281.56 

35 

1516 

88 

38 

12 

141 

61 

07 

194 

84-03 

247 

106.99 

675 

292.40 

36 

15-59 

89 

38 

55 

142 

61 

51 

195 

84.47 

248 

107-43 

700 

303-22 

37 

16.02 

90 

38 

98 

143 

61 

94 

196 

84 . 9.0 

249 

107.86 

725 

314-05 

38 

16.45 

•91 

39 

42 

144 

62 

37 

197 

85-33 

250 

108.29 

750 

324.88 

39 

16.89 

92 

39 

85 

14s 

62 

81 

198 

85.76 

251 

108.73 

775 

335-72 

40 

17-32 

93 

40 

28 

146 

63 

24 

199 

86.20 

252 

109. 16 

800 

346.54 

41 

17-75 

1  94 

40 

72 

147 

63 

67 

200 

86.63 

253 

109.59 

825 

357-37 

42 

18.19 

95 

41 

15 

148 

64 

10 

201 

87-07 

254 

110.03 

850 

368.20 

43 

18.62 

96 

41 

58 

149 

64 

54 

202 

87.50 

255 

I  JO. 461 

875 

379-03 

44 

19-05 

97 

42 

01 

150 

64 

97 

203 

87-93 

256 

110.89 

900 

389.86 

45 

19.49 

98 

42 

45 

151 

65 

40 

204 

88.36 

257 

111.32 

925 

400.70 

46 

19.92 

99 

42 

88 

152 

65 

84' 

205 

88.80 

258 

III .76 

950 

411-54 

47 

20.35 

TOO 

43 

31 

153 

66 

27, 

206 

89.21 

259 

112.19 

975 

422.35 

48 

20.79 

lOI 

43 

75 

154 

66 

70 

207 

89.66 

260 

112.62 

1000 

433-18 

49 

21 .22 

102 

44 

18 

155 

67 

14 

208 

90.10 

261 

113.06 

1500 

649-70 

50 

21.65 

103 

44 

61 

156 

67 

57 

209 

90.53 

262 

113-49 

2000 

866.30 

51 

22.09 

104 

45 

OS 

157 

68 

00 

210 

90.96 

270 

116.96 

3000 

1299-50 

52 

22.52 

105 

45 

48! 

158 

68 

43 

211 

91-39 

275 

119. 12 

5? 

22.95 

106 

45 

91^ 

159 

68.87 

212 

91  83 

280 

121 .29 

354 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


AREAS   OF   CIRCLES,   ADVANCING   BY   EIGHTHS 
Areas 


E 

1 

1 

3 

1 

3 

7 

S 

0 

8 

4 

8 

2 

' 

4 

8 

o 

.0 

.0123 

.0491 

.1105 

.1964 

.3068 

.4418 

.6013 

1 

•7854 

.9940 

I .2272 

I . 4849 

1. 7671 

2.0739 

2-4053 

2.7612 

2 

3-14 

3-55 

3-98 

4-43 

4.91 

5-41 

5-94 

6.49 

3 

7 

07 

7.67 

8 

30 

8.95 

9.62 

10 

32 

11.05 

11.79 

■  4 

12 

57 

13-36 

14 

19 

15-03 

15-90 

16 

80 

17.72 

18.67 

,  5 

19 

64 

20.63 

21 

65 

22.69 

23 .  76 

24 

85 

25-97 

27.11 

■  6 

28 

27 

29.47 

30 

68 

31.92 

33-18 

34 

47 

35-79 

37-12 

'  7 

38 

49 

39  87 

41 

28 

42.72 

44.18 

45 

66 

47-17 

48.71 

1  8 

50 

27 

51-85 

53 

46 

55-09 

56.75 

58 

43 

60.13 

61.86 

9 

63 

62 

65.40 

67 

20 

69.03 

70.88 

72 

76 

74.66 

76.59 

lO 

78 

54 

80.52 

82 

52 

84.54 

86.59 

88 

66 

90.76 

92.89 

II 

95 

03 

97.21 

99 

40 

101.62 

103.87 

106 

14 

108.43 

110.75 

12 

113 

10 

"5-47 

117 

86 

120.28 

122.72 

125 

19 

127.68 

130.19 

13 

132. 

73 

135-30 

137 

89 

140.50 

143-14 

145 

80 

148.49 

151.20 

14 

153 

94 

156.70 

159 

48 

162 .30 

165.13 

167 

99 

170.87 

173.78 

15 

176 

71 

179.67 

182 

65 

185.66 

188.69 

191 

75 

194.83 

197-93 

i6 

201 

06 

204.22 

207 

39 

210.60 

213.82 

217 

08 

220.35 

223.65 

17 

226 

98 

230.33 

233 

71 

237.10 

240-53 

243 

98 

247.45 

250.95 

i8 

254 

47 

258.02 

261 

59 

265.18 

268.80 

272 

45 

276.12 

279.81 

19 

283 

53 

287.27 

291 

04 

294.83 

298.65 

302 

49 

306.35 

310.24 

20 

314 

16 

318.10 

322 

06 

326.05 

330.06 

334 

10 

338.16 

342.25 

21 

346 

36 

350.50 

354 

66 

358.84 

363-05 

367 

28 

371-54 

375  83 

22 

380 

13 

384.46 

388 

82 

393 ■ 20 

397.61   402 

04 

406 . 49 

410.97 

23 

415 

48 

420.00- 

424 

56 

429-13 

433 • 74 

438 

36 

443-01 

447 . 69 

v24 

452 

39 

457-" 

461 

86 

466.64 

471.44 

476 

26 

481 .11 

485.98 

25 

490 

87 

495-79 

500 

74 

505-71 

510.71 

515 

72 

520.77 

525.84 

26 

530 

93 

536-05 

541 

19 

546-35 

551-55 

556 

76 

562.00 

567.27 

27 

572 

56 

577-87 

583 

21 

588.57 

593-96 

599 

37 

604.81 

610.27 

28 

61S 

75 

621.26 

626 

80 

632.36 

637-94 

643 

55 

649.18 

654.84 

29 

660 

52 

666.23 

671 

96 

677.71 

683.49 

689 

30 

695-13 

700 . 98 

3° 

706 

86 

712.76 

718 

69 

724.64 

730.62 

736 

62 

742.64 

748.69 

31 

754 

77 

760.87 

766 

99 

773-14 

779-31 

785 

51 

791.73 

797.98 

32 

804 

25 

810.54 

816 

86 

823.21 

829.58 

835 

97 

842.39 

848.83 

35 

855 

30 

861.79 

868 

31 

874-85 

881.41 

888 

00 

894.62 

901 . 26 

34 

907 

92 

914.61 

921 

32 

928.06 

934.82 

941 

61 

948.42 

955  25 

35 

962 

II 

969 . 00 

975 

91 

982.84 

989.80 

996 

78 

1003 .8 

1010.8 

36 

1017 

9 

1025.0 

1032 

I 

1039.2 

1046 . 3 

1053 

5 

1060. 7 

1068.0 

37 

1075 

2 

1082.5 

1089 

8 

1097. I 

1104.5 

mi 

8 

1119.  2 

1 1 26. 7 

38 

"34 

I 

1141 .6 

"49 

01 

1156.6 

I 164. 2 

1171 

7 

"79-3 

1186.9 

39 

1194 

6 

1202.3 

1210 

0 

1217.7 

1225.4 

1233 

2 

1 241 .0 

1248.8 

40 

1256 

6 

1264.5 

1272 

4 

1280.3 

1288.2 

1296 

2 

1304.2 

1312.2 

41 

1320 

3 

1328.3 

1336 

4 

1344-5 

1352.7 

1360 

8 

1369.0 

1377.2 

42 

1385 

4 

1393-7 

1402 

0 

1410.3 

1418.6 

1427 

0 

1435-4 

1443.8 

43 

1452 

2 

1460.7 

1469 

I 

1477.6 

1486.2 

1494 

7 

1503-3 

15". 9 

44 

1520 

5 

1529.2 

1537 

9 

1546.6 

1555.3 

1564 

0 

1572.8 

1581.6 

45 

1590 

4 

1599-3 

1608 

2 

1617.0 

1626.0 

1634 

9 

1643-9 

1652.9 

46 

1661 

■9 

1670.9 

1680 

0 

1689. I 

1698.2 

1707 

4 

1716.5 

1725.7 

47 

1734 

■9 

1 744  -  2 

1753 

5 

1762.7 

1772. I 

1781 

4 

1790.8 

I 800 . I 

48 

1809 

.6 

1819.0 

1828 

5 

1837-9 

1847-5 

1857 

0 

1866.5 

1876. I 

49 

1885 

•7 

1895-4 

1905 

.0 

1914-7 

1924.4 

1934 

2 

1943-9 

1953.7 

50 

1963 

•5 

II973-3 

1983 

.2 

Ii993-i 

2203.0 

2012 

9 

2022.8 

2032.8 

APPENDIX  N 


355 


TABLE   GIVING   RATIOS   OF   AREAS 

For  given  diameters  of  steam  and  water  cylinders. 


V  QJ  U 


Diameter  of  Steam  Cylinders. 


3 

3i 

4 

5 

6 

7 

8           9 

1 

10      1      12       1      14 

i        j 

23.04 

31.36 

40.97 

64.01 

92.16  125.45  163.85  207. 37|256. 00^368. 64 

501.76 

I        1 

16.00 

21.77 

28.45 

44.45 

64.00 

87.12 

113.78  144.00  177.77  2.56.00 

.348.44 

i 

11.75 

16.00 

20.90 

32,66 

47.02 

64.01 

83.60 

105.80  130,61!  188. 09 

2.56.00 

1 

9.00 

12.25 

16.00 

25.00 

36.00 

49.01 

64.00 

81.00  100.00  144.00 

196.00 

u 

7.11 

9.68 

12.65 

19.76 

28.44 

38.73 

50.. 57 

64.00 

79,01  113.77 

154.87 

li 

5.76 

7.84 

10.24 

16.00 

23.04 

31.37 

40.97 

51.85 

64.00;  92.18 

125.46 

11 

4.76 

6.48 

8.46 

13.23 

19.04 

25.92 

.33.85 

42.84 

52.89    76.16 

103.66 

11 

4.00 

5.44 

7.11 

11.12 

16.00 

21.78 

28.45 

36.00 

44.45    64.00 

87.12 

.   If  ' 

3.41 

4.64 

6.06 

9.47 

13.63 

18.56 

24.24 

30.68 

37.87    54.53 

74.22 

li 

2.94 

4.00 

5.23 

8.17 

11.75 

16.00 

20.90 

26.45 

32.66    47.03 

64.00 

u 

2.56 

3.48 

4.55 

7.11 

10.24 

13.94 

18.21 

23 .  04 

28.44    40.96 

55 .  75 

2 

2.25 

3.06 

4.00 

6.25 

9.00 

12.26 

16.00 

20.26 

25.00    36.00 

48.09 

2i 

1.78 

2.42 

3.16 

4.93 

7.10 

9.67 

12.63 

15.98 

19.73    28.42 

38.68 

2i 

1.44 

1.96 

2.56 

4.00 

5.76 

7.84 

10.24 

12.96 

16.00    23.04 

31.35 

2! 

1.19 

1.62 

2.12 

3.31 

4.76 

6.48 

8.46 

10.72 

13.22    19.04 

25.92 

3 

1.00 

1.36 

1.78 

2.78 

4.00 

5.43 

7.11 

9.00 

11.11    16.00 

21.77 

3i 

.85 

1.16 

1.51 

2.37 

3.40 

4.64 

6.06 

7.67 

9.46    13.63 

18.. 55 

3§ 

.73 

1.00 

1.31 

2.04 

2.94 

4.00 

5.23 

6.61 

8.17    11.76 

16.00 

31 

.64 

.87 

1.14 

1.78 

2.56 

3.48 

4.55 

5.76 

7.11    10.24 

13.93 

4 

.56 

.77 

1.00 

1.56 

2.25 

3.06 

4.00 

5.06 

6.25      9.00 

12.25 

M 

.50 

.68 

.89 

1.38 

1.99 

2.71 

3.54 

4.49 

5.53      7.97 

10.85 

M 

.44 

.61 

.79 

1.23 

1.78 

2.42 

3.16 

4.00 

4.94      7.11 

9.68 

41 

.40 

..54 

.71 

1.11 

1.60 

2.17 

2.84 

3.59 

4.43      6.38 

8.68 

5 

.36 

.49 

.64 

1.00 

1.44 

1.96 

2.56 

3.24 

4.00      5.76 

7.84 

51 

.30 

.40 

.53 

1.00 

1.19 

1.62 

2.12 

2.68 

3.30     4.76 

6.48 

6 

.25 

.34 

.45 

.83 

1.00 

1..36 

1.78 

2.25 

2.78     4.00 

5.45 

61 

.29 

..38 

.69 

.85 

1.16 

1.51 

1.92 

2.37     3.40 

4.64 

7 

.25 

.33 

.59 

.73 

1.00 

1.31 

1.65 

2.04 

2.94 

4.00 

7i 

.28 
.25 

.51 
.44 

.39 
.35 
.31 
.28 
.25 

.64 
.56 

.50 
.44 
.40 
.36 
.33 
.30 

.25 

.87 
.77 

.68 
.60 
.54 
.49 
.44 
.40 

.34 
.29 
.25 

1.14 
1.00 

.89 
.79 
.71 
.64 
.58 
.53 

.44 
.38 
.33 
.28 
.25 

1.44 
1.27 

1.12 
1.00 
.90 
.81 
.73 
.67 

.56 
.48 
.41 
.36 
.32 
.28 
.25 

1.78 
1.56 

1.38 
1.23 
1.11 
1.00 
.91 
.83 

.69 
.59 
.51 
.44 
.39 
.35 

2.56 
2.25 

1.99 
1.78 
1.60 
1.44 
1.31 
1.19 

1.00 
.85 
.74 

3.48 

8 

3.06 

8? 

2.71 

9 

2.42 

91 

2.17 

10 

1,96 

10^ 

1,77 

11 

1,62 

12 

1.36 

13 

1.16 

14 



1.00 

15 

.64        .87 

16 

.56        .76 

17 

.50        .68 

18 

.31        .45        .60 



356  SUBWAYS   AND  TUNNELS  OF  NEW  YORK 

TABLE  GIVING  RATIOS  OF  AREAS— iConli>tiicd) 


t-  1-  w 
^  OJ  ti 

Diameter  of  Steam  Cylin 

ders. 

Soc^ 

i6 

i8 

20 

22 

24 

26 

28 

30 

32 

34 

36 

1 

1 

455.09 

1 

334 . 37 

256.00  324.00  400.00 

ij 

202.27 

256.00  316.05 

]^i 

163.86 

207.38 

256.00  309.81 

If 

135.39 

171.47 

211.69  256.00 

li 

113.78 

144.00 

177.77 

215. 11 '256. 00 

1- 

96.94 

122.72 

151.54  183.37'218.22 

•  11 

83.60 

105.79 

130.61 

158. 05: 188. 10  220.71 

11 

72.82 

92.16 

113.78 

137.67 

163.85  192.29 

2 

64.00 

81.00 

100.00 

121.00 

144.00,169.00 

196.00 

225.00  256.00 

2i 

50.56 

64.00 

79.01 

95.60 

113.78131.56 

154.87  177.77 

202.27 

2J 

40.96 

51.84 

64.00 

77.44 

92.16  108.16 

125.44  144.00 

163.84  184.97 

2J 

33.85 

42.84 

52.89 

64.00 

76.17 

89.39 

103.66  119.01 

135.41  152.86 

3 

28.44 

36.00 

44.44 

53 .  77 

64.00 

75.11 

87.11  100.00 

113.77 

128.44 

144.00 

3i 

24.23 

30.67 

37.87 

45.83 

54.54 

64.00 

74.24 

85.22 

96. 96' 109. 46 

122.72 

31 

20.90 

26.44 

32.65 

39.42 

47.02 

55.18 

64.00 

73.47 

83.59 

94.36 

105.79 

3f 

18.20 

23.04 

28.44 

34.42 

40.96 

48.07 

55.75 

64.00 

72.82 

82.21 

92.16 

4 

16.00 

20.25 

25.00 

30.25 

36.00 

42.25 

49.00 

56.25 

64.00 

72.25 

81.00 

4i 

14.17 

17.93 

22.14 

26.79 

31.89 

37.43 

43.41 

46.51 

56.69 

64.00 

71.76 

4J 

12.64 

16.00 

19.75 

23.90 

28.44 

33.33 

38.71 

44.44 

50.56 

57.08 

64.  CO 

4i 

11.34 

14.36 

17.73 

21.45 

25.53 

29.96 

34.75 

39 .  89 

45.38 

51.24 

57.44 

5 

10.24 

12.96 

16.00 

19.20 

23.04 

27.04 

31.36 

36.00 

40.96 

46.24 

51.84 

51 

8.46 

10.71 

13.22 

16.00 

19.04 

22.33 

25.91 

29.75 

33.85 

38.21 

42.84 

6 

7.11 

9.00 

11.11 

13.44 

16.00 

18.77 

21.77 

25.00 

28.44 

32.11 

36.  CO 

6^ 

6.06 

7.66 

9.46 

11.45 

13.63 

16.00 

18.56 

21.30 

24 .  23 

27.36 

30.67 

7 

5.22 

6.61 

8.16 

9.87 

11.75 

13.79 

16.00 

18.37 

20.90 

23.59 

26.44 

7i 

4.55 

5.76 

7.11 

8.60 

10.24 

12.00 

13.93 

16.00 

18.20 

20.55 

23.04 

8 

4.00 

5.06 

6.25 

7.25 

9.00 

10.56 

12.25 

14.06 

16.00 

18.06 

20.25 

8J 

3.54 

4.48 

5.53 

6.69 

7.97 

9.35 

10.85 

12.45 

14.17 

16.00 

17.92 

9 

3.15 

4.00 

4.93 

5.85 

7.11 

8.34 

9.67 

11.11 

12.64 

14.27 

16.00 

9^ 

2.83 

3.59 

4.43 

5.36 

6.38 

7.49 

8.68 

9.97 

11.34 

12.88 

14.36 

10 

2.56 

3.24 

4.00 

4.84 

5.76 

6.76 

7.84 

9.00 

10.24 

11.56 

12.96 

10^ 

2.32 

2.94 

3.63 

4.39 

5.22 

6.13 

7.10 

8.16 

9.29 

10.48 

11.75 

11 

2.11 

2.67 

3.30 

4.00 

4. 76 

5.58 

6.47 

7.43 

8.46 

9.55 

10.71 

12 

1.77 

2.25 

2.77 

3.36 

4.00 

4.67 

5.44 

6.25 

7.11 

8.02 

9.00 

13 

1.51 

1.91 

2.37 

2.86 

3.40 

4.00 

4.63 

5.32 

6.06 

6.83 

7.66 

14 

1.30 

1.65 

2.04 

2.46 

2.93 

3.44 

4.00 

4.59 

5.22 

5.89 

6.61 

15 

1.13 

1.44 

1.77 

2.13 

2.56 

3.00 

3.48 

4.00 

4.55 

5.13 

5.76 

16 

1.00 

1.26 

1.56 

1.89 

2.25 

2.64 

3.0G 

3.51 

4.00 

4.51 

5.06 

17 

.88 

1.12 

1.38 

1.67 

1.99 

2.34 

2.71 

3.11 

3.54 

4.00 

4.48 

13 

.79 

1.00 

1.23 

1.49 

1.77 

2.08 

2.41 

2.77 

3.15 

3.56 

4.00 

APPENDIX  N 


357 


O  "^  O:  0\  ^  ^'  O  tr^<'    '     ' 
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<OOoo  roO  OXO  »0^ 


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M  f?  "^  >0*0  »^ 


M  -^  ^00  r-O 


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r-sC  O  t^O  -l-OX  t-r-^u*,  r«5" 


Tfi^ONN  Tft^O  i^t-C  'tl^' 


iTi  O^  nx  0\  t 


'  ro  O^  arffOO'C  'to 


i  r^f^'^T't^xfiinifit^t^O^t 


I  rox  X^X         \0-^00r-—  •-t^'^'1-       X'O        f^CO'-'Ov 

3  rj-  rtsO  O  ■^•-•Xt^r^Or^  r-i^O  CO'"'  '^^  "^  —  O  "^X  x  M  r*X>0  0   ©■  "1-  r^  ir.x        ' 

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ro  ro  ro  ro  't  toO  X  X  0»  ^ 


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358 


SUBWAYS   AND   TUNNELS   OF  NEW   YORK 


W      . 
H 

o     -S 

H       1 

g  8  S 

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O   o-  I 
o  g  g, 

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0000'-''-''-''-*WMroro  "TO  0<N0  O  iCOO  roO.  t— icrocN  M  r^  w  ro  ""I-O   O 


000000000000000<- 


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QJ    C    O 


p.s 


00  O  PO'Ct^O'-t  roicr^O"-"  POM  Ooo  r^icpof^  Ooo  t-^opow  ooo  r^ioroN  Ooo*-* 
OO  »-'0  ■-'O  P^  r-r-i  i^CNOO  POT'C  icO  r-co  OOOmwpO'Tic  icO  t^oo  O  O  O 
w  N  ro  PO  ■^  '^  uo  mo  O  i>  r^oo  O  r^)  -^O  oo 

OOOOOOOOOOOOOMMMhHt-. 


*ol2""H2-"MS-"-d: 


APPENDIX  N 


359 


E 
u 

£ 
o 

H 
W 


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o 

N 

JS 
o 
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00 

tOOLoM     ri     fOO     MOO    *^CC     O 

l-tM»HMOIWC4CO 

r<    t^   1/-J  lo  i^   "N    Ov  r^   O    <^   O    O  O 

MiHi-iMriMrOro<^ 

oOtoiooOiNOioOooOvnMiNiy^ 

COlOt^OvC^     loco     <M     lOO      ^0^•^0^ 

J3 

<M0'O'^iM"NC0iN0<2I^00r0f0lO 
Tj-u-ji^O    -to    0    loO    loOO    "^O    J^ 

c 

o 

c 

o 

■^lO^O    Oror--tN    t~»rs    0>0    ^ow    OOOOO 
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">. 

o 

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u 

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E 

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t^OO      "      UOCO      t^i^l      rOO      Tj-MOOOOOOOOO      <^i 

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M     M     M     1^1     <^rOT}-lOlOOt^CO     O 

.2 

r0ioC>iOTl-!^t-)vo0     000r0\0'O'*00    0 
rOTtior^ON!r)OOt^Ot^-^!r)'Noiro-*r^     ' 
iHi-(OirO":>T)-uovot^oOO\0 

00 

Mt^Loiox^OcOOOOr^iooOON-*      '      '      '       i 

MMCNcopo'^iovot^ovo    ;    ;    ; 

J5 

1 

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MM<Nro<r)Tt\ot^ooo    ;    ;    ;    ;    ; 

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c 

J2 

' 

lO-^ro^-^O-^OMM                                              ■' 

t^r^ioriO-^ONMOO 

MMDCOCO-*vOOO.                              ...                              .: 

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O 

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N-^0\OoOroiOPO 

0<~O000rOt^<~0                                            ... 

MMCNr^rJ-ioOGO 

C 
(-1 

r^   oi    o    '^  oo  00    ^J                                                                                                  1 

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M     i-(     ro    -^    lO   t^    Ov 

o 

o  o  o  to  o    .    ::::::;■.'.::;::   : 

roOOt^tN 

Mr0-+O0 ; 

5"' 

3c 

l-,ml-.i-IMCNC4P)C<MrOrOfOfO 

1 

360 


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^ 

o 

in 
< 

z 

O 

■/I 

z 

^ 

y 

S 

< 

Q 

H 

§ 

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Pi 

a 

o 

'f 

Ph 

H 

C/i 

w 

p:< 

fin 

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>— ( 

|1h 

H 

Ht 

iz; 

o 

H 

Pi 

HH 

UI 

ffi 

o 

^ 

o 

c^ 

^ 

Contents 

in 

Gallons. 

per  Foot. 

o 
o 
o 

Or^iNOcOOOoOn 

O    O    "     1^1     -=1-  O     O  O 
OOOOOOO" 

O     CO  CO   00    CO                              _ 
tor^O^<NNO    O     O^ONt-t    0     '-' 

too      ONtOCvj      CMO      Onm      OOO 

CN     CO'^OOO    O    -^OnO     coo 

CO  r-» 

OnOO 

tH       M       IH       CM       CO     ■^ 

Tl-     to 

Number 
of 

Threads 
per  Inch, 
of    Screw. 

:^ 

^IN  -HlN  tH[W 

so    CO     Tl-    '^    w     w     M 

HIN 

00   00   CO 

COOOOOOOCOCOOOCO 

00   00 

Nominal 
Weight 
per  Foot. 
Pounds. 

(N       H      VO  VO               00       -^     I-^ 

t1-u->oo     hvO     (NOVO 

cot^toco         Ti-t^       ooi^M 
r^ioO    t^cotor^-^coOO 

CO 

O      On 

O 

H       H       Ol       (N 

CO 

to  t^   On 

OcMTtoOcooO-cTO 

MI-lt-IMCMCMCO*^ 

to  00 

Length  of 
Pipe  Con- 
taining I 

Cubic 

Foot. 

Feet. 

o 

O     >0^0     OvtMvO     CO 

H     On  O 

H       Tf     to 

1-1    coOoO    MCOO    O 
roO     <Ni     ONt^oO     OIOO 

O    t~- 

to     CM 

o 
o 

lO   M     1^1     0    -O  vO    O 
CO    lo   t^   t^  vo     0\  i-~ 
ro    t^    ^    <N     M 

^ 

O     ON    T)- 

CO   t-<     w 

M      ONt^^COCM      CM      M 

M       M 

ON 

O\00     ■^  O     t^    Tj-    lO 
tN      lO    to  \0      lO  O      fO 
IN     CO   >0  00     ro    1-1    00 

O 

CO 

HMO 

On    IN    O 
■^  O     to 

Tj-tOOiM       coo      tOC) 

O     coOvt^O     CM     wO 
OnO     <N     ^O     Ttt--I^ 

CO   t^ 
'i-  O 

M      CM      CN 

'd-    NO        ON     "N 

toONTtrJ-tooo    roO 
M     M    cs     ro'i-tot^ON 

1 H" 

Internal 
Area. 
Inches. 

o 

M    O    00     CO    (^ 
•+    M     Tt-    CO    cs    vO    CO 
O     O    O     CO  vO     O    CO 
H     H     CO    lO  00     'i-    O 

to    CO  00     1^ 

to  CO    CO    CO 
CO    t^    CO  OO 

O     OnO     ONt^ONCooO 
cOcoOnOO     cocococo 
I^OnOnOO     t^OOOO 

?o 

M       CM 

CO 

•^   !>•    On 

CS     ioOnOOOO     O     cooo 

MMMCMCOtOOt^ 

to    CO 

ON     M 

Length  of 
Pipe  per 
Square 
Foot  of 
Outside 
Surface. 
Feet. 

lo   r^   (^1    i-^   CO   M 
i-^  lo  O    CO   O    O    M 
O    O     uo  so     0^    CO    O 

o 

^        HH       tOONtOONt^tO'rt-1">0 

•^1     0\  to   '^  o     c>i    i:-^   O     -^   On   to 

cOO      OnCO      f^O     toto-^coco 

IN      O 
CO    CO 

c^ 

I-^    lO     ":!-     CO     CS      C<      IN 

M 

H       M 

Length 
of  Pipe  per 
Square 
Foot  of 
Inside 
Surface. 
Feet. 

lO 

to     0\  CO      M    00 
O     J^    CO    CO    t^  O     t^    -^ 
lO  O     M    O    O     t^    CO  CO 

r^  to  r^ 

-t   -t  t^ 

to     D       O 

On  CO      t^              Tf  CO      to    M 
^     -1-     >0     CO     ^     t^     c^     CO 

a  CO   t^  o   to  ^  ■*  ^o 

■*     CM 

CO   CO 

"+ 

0      t-~  -O      ^    CO    <N      O) 

" 

M        l-l        1-1 

External 
Circum- 
ference. 
Inches. 

IN 

M 

\0     H     CM     On   •*   to    On 

0\   <N     to    On   CO   M   \o 
NO     M    NO     CM     t-t     CM     On 

H 
NO 

CN    O    O 
CO    0^  O 
O      On    to 

t~-00      tOCO-^O      COCM 

coo     l-^M     loO<cot-~ 
l-l    t^Ttoo     OnO     -Jj-i^ 

M       >0 

ON     O 

M      CM      04      CO    ■*     to    to 

t^ 

On    0      i^l 

l-l      l-l 

-t    lO    t^    O     CO    I^    O     "O  O     O 

M        M        M        -Nl        1^1        ^J        to      rO      CO     --J- 

Internal 
Circum- 
ference. 
Inches. 

00 

CO 

Tj-    (N     r~-    On    IN     to    H 
^    to    to  00      On    CO  O 

HH      to     On    to    CM      CO     0 

o> 

rt-  o  o 
to    CO    "+ 

l^    O        M 

00     coOn'^coO    r>»lO 
■^lo-^too    r^t^i-^ 

OmoOOOOcmvI- 

to  O 
to  t^ 

M      M      M      M      CO     •*     to 

■o 

t^    0-,    l-l 

C-)      -t-toONCM      toOO      w 
Mh-ll-IHHCMCMCMfO 

<0    CO 

Actual 

Outside 

Diameter. 

Inches. 

O 

to               to 

^      I^      Tt      to      M      NO 

to  NO    CO     0     CO  O     0\ 

to    to 

CO  »3     to    O 

CO   to   to   to  00 

O     CM     c-1     r^   00    to 

too   tooooo   t^ 

to  to 

H       M       H       M 

N 

"N      CO    Tt- 

rt-toioo    t^OO     OnO 

M      CM 

M      H 

Actual 

Inside 

Diameter. 

Inches. 

o 

■*    ^    CO    ^  oo     O     M 

O       0>     CM       CM       ^   00       M 

CO    't  O    CO     O     CO  NO 

t^  00     1^  00 

NO    NO    NO     >-< 
O     '^   O    to 

OOOtotococ^     M     O^ 
cmO^O<noOOi-i 
OtoOOOONOO 

o   o 

H       M       M 

(N 

CM     CO    CO 

•^Tj-too    t^r^ONO 

M      04 

IH        l-l 

^1         u 

ca  jj  0) 
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^"5 

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rtl^  05|tO  rHiN  nl-d               rt|*-lN 
t-t        l-l       M 

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CM      CO     C*"- 

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M       (N 

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AP}»ENI)IX   N 


361 


p;     a 


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Oallons 

Dis- 
charged 

per 
Minute. 

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10 

0 

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8 

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Friction 
Loss  in 
Pounds. 

8    : 

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0    ■ 

0    ': 

0 

•^1   0   c:    10  re  0 
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>   C 

APPENDIX   N 


363 


POUNDS  PRESSURE  LOST  BY  FRICTION 

In  each  lOO  feet  of  2s-inch  fire  hose,  for  given  discharges  of  water  per  minute. 


Pressure  at  Hose  Nozzle. 


°l 


Head  in  pounds  per  sq  in.      20 
Head  in  feet 46 .  2 


69.3    92.4 


60 


115-5  138.6  161. 7  184.8 


207.9  231 .0 


Is 


ll 


Gallons  discharged. .  .  . 
•;  Rubberhose,  pounds.. 
I  Leather  hose,  pounds  . 

I  Gallons  discharged. .  .  . 

<  Rubber  hose,  pounds. . 
^  Leather  hose,  pounds. . 

I  Gallons  discharged. .  .  . 
'  Rubber  hose,  pounds. . 
I  Leather  hose,  pounds. . 

Gallons  discharged. .  .  . 

<  Rubber  hose,  pounds. . 
1^  Leather  hose,  pounds  . 


no 
4-35 
6.33 

139 

6.79 

9.05 


134     liSS 
6.40]   8.40 
8.53:10.83 


10. 16 

12.  71 


196 
13-60 
16.38 


173 
10.  20 
13.10 

219 
17.05 
20.  II 


210         242 
10.28   15.64  20.85  25.46 

12.84  19-0   '24.07  30. II 

207         253         293         327 
15.0      22.96:29.4040.50 

18.81  26.39'35.oi  43-38 


189       205       219 
12.80  14.80  17.0 
15-34  17.79  20.11 

240  I  259 
20.59  24.0 
23.88  27.61 


297 
29 .  50 
35-94 


320 
39.0 
4157 


3I-41 

342 
43-81 
47.36 


232       245 
19.20  20.50 
22.40  24.83 

294  i  310 
30.0  33.0 
35-24  3907 

363  I  383 
49-42  55-0 
53-25  59-20 


358       387       413       439   I   462 
48.2055.7064.7072.0     79.26 
52.0    60.4068.5976.7384.87 


HORIZONTAL  AND  \ERTICAL  DISTANCES  REACHED  BY  JETS 


0   Xi 

Pressure  at 

\OZZLE. 

4)        . 
.2     N 

Head  in  pounds  per  sq.  in. 

20 

30 

40 

50 

60 

70 

80 

90 

100 

"g; 

Head  in  feet      

46.2 

69.3 

92.4 

115. 5 

138.6 

161 .7 

184.8 

207.9  2310 

[  Gallons  discharged 

no 

134 

155 

173 

189 

205 

219 

232 

245 

I 

•!  Horiz.  distance   of  jet  . 

70 

90 

109 

126 

142 

156 

168 

178 

186 

1  Vertical  distance  of  jet  . 

43 

62 

79 

94 

108 

121 

131 

140 

148 

I  Gallons  discharged 

131 

170 

196 

219 

240 

259 

277 

294 

310 

i| 

^  Horiz.  distance  of  jet  . 

71 

93 

113 

132 

148 

163 

175 

186 

193 

[  Vertical  distance  of  jet  . 

43 

63 

81 

97 

112 

125 

137 

148 

157 

[  Gallons  discharged 

171 

210 

242 

271 

297 

320 

342 

363 

383 

U 

<  Horiz.  distance  of  jet  . . 

73 

96 

118 

138 

1 56 

172 

186 

198 

207 

Vertical  distance  of  jet  . 

43 

63 

82 

99 

115 

129 

142 

154 

164 

j  Gallons  discharged 

207 

253 

293 

327 

358 

387 

413 

430 

462 

If 

<  Horiz.  distance  of  jet .  . 

75 

100 

124 

146 

166 

184 

200 

213 

224 

^  Vertical  distance  of  jet  . 

44 

65 

85 

102 

118 

133 

146 

158 

169 

364 


SUBWAYS  AND  TUNNELS  OF  NEW  YORK 


FRENCH  OR  METRIC   MEASURES 

The  metric  unit  of  length  is  the  meter  =  39.37  inches. 
The  metric  unit  of  weight  is  the  gram  =  15.432  grains. 

The  following  prefixes  are  used  for  sub-divisions  and  multiples:  Milli  =  yo^o  0^, 
Centi  =  yoo'  I-^sci  =  xV>  Deca  =  io,  Hecto  =  ioo,  Kilo  =1000,  Myria=  10,000. 

FRENCH  AND   BRITISH   (and  American)  EQUIVALENT    MEASURES 
Measures  of  Len'gth 

British  and  U.  S. 
=  39.37  inches,  or  3.28083  feet,  i. 09361  yards. 


French. 
I  meter 
.3048  meter 
I  centimeter 


=  I  foot. 

=  .3937  inch. 
2.54  centimeters  =  I  inch. 

I  millimeter        =.03937  inch,  or  2^5-  inch  nearly. 
25.4  millimeters  =  i  inch. 
I  kilometer  =1093.61  yards,  or  .62137  mile. 

Measures  of  Capacity 

j  61.023  cubic  inches. 

,.        ,  ,  .     ,     .  s  -o^su  cubic  foot. 

I  liter  (=  I  cubic  decimeter)  = 


28.317  liters 
4.543  liters 
3.785  liters 

French. 
I  gram 
.0648  gram 
28.35  gram 
I  kilogram 
.4536  kilogram 

I  tonne  or  metric  ton    1 
1000  kilograms  1 


1. 016  metric  tons 
1016  kilograms 


.2642  gallon  (American). 
[    2.202  pounds  of  water  at  62°  F. 
=        I  cubic  foot. 
=        I  gallon  (British). 
=        I  gallon  (American). 

Measures  of  Weight 

British  and  U.  S. 
=       15-432  grains. 
=         I  grain. 
=         I  ounce  avoirdupois. 
=  2.2046  pounds. 

=         I  pound. 

'  .9842  ton  of  2240  pounds. 
19.68  rwts. 
2204.6  pounds. 

I  ton  of  2240  pounds. 


COAL   CONSUMPTION 

The  average  coal  consumption  may  be  taken  as  follows,  an  evaporation  of 
8  pounds  of  water  to  i  pound  of  coal  being  assumed: 

For  non-condensing  engines 3       to  5I  per  I.H.P.  per  Hour. 

For  condensing  engines 2       to  4 

For  compound  non-condensing  engines 2.5  to  3 

For  compound  condensing  engines 1.6    to  2.75 

For  triple  condensing  engines 1.25  to  1.75 

For  quadruple  condensing  engines i       to  1.5 


APPENDIX   N 


3b5 


HEAT  OF   COMBUSTION   OF   FUELS 

Air  Required  per  Total  Heat  of 

Pound  of  Fuel  in  Combustion  of 

Cubic  Feet  at  i  Pound  of 

62°  F.  Fuel  in  B.T.U. 

Coal 140  14 .  700 

Coke 142  13  548 

Lignite 116  13 .  108 

Asphalt 156  17.040 

Wood,  dry 80  10.974 

\\'ood,  20  per  cent  moisture 60  7-951 

Wood  charcoal,  dry 125  13.006 

Peat,    dry 99  12  .  279 

Peat,  30  per  cent  moisture 69  8.260 

Straw 56  8 .  144 

Petroleum 188  20.411 

Petroleum  oils 235  27.531 

Coal  gas,  per  cubic  foot  at  62°  F .630 

In  practice  it  is  found  that  from  18  to  24  pounds  of  air  is  required  for  the 
combustion  of  each  pound  of  coal,  according  to  whether  forced  or  natural  draft 
is  used. 


FEED-WATER   CONSUMPTION 

Average  weight  of  feed- water  used  per  I.H.P.  per  hour,  in  pounds. 

Water 

Type  of  Engine.                                                         Boiler  Pressure.  Consumption. 

Slide  valve,  throttling N.C.                    80  35  to  45 

Automatic  expansion  gear N.C.                    80  30  to  35 

Automatic  expansion  gear N.C.                   100  26  to  30 

Compound  automatic  expansion  gear .  N.C.                   100  241028 

Compound  automatic  expansion  gear.     C.                     100  18  to  24 

Compound  automatic  expansion  gear.  N.C.                   125  21  to  25 

Compound  automatic  expansion  gear.      C.                      125  16  to  20 

Simple  Corliss N.C.                    So  25  to  30 

Simple  Corliss C.                      80  22  to  25 

Compound  Corliss C.                      100  16  to  20 

Compound  Corliss C.                     125  15  to  19 

Triple  expansion C.                     125  14  to  16 

Triple  expansion C.                     150  13  to  15 

Compound  superheated  steam C.                     i8c  10  to  12 

C,  condensing;  N.C,  non-condensing. 


INDEX 


PAGES 

Air  Compressors  on  New  York  Tunnel  Work 185-204 

Air  Compressor  Plant: 

Belmont  Tunnels 148-152 

Bergen  Hill  Tunnel 53~5S 

Cross-Town  Tunnels  P.  R.R 105-106 

East  River  Tunnels,  P.  R.R 114-121 

Hudson-Manhattan  Tunnels 166-167 

North  River  Tunnels,  Manhattan  Side,  P.  R.R 58-62 

North  River  Tunnels,  Weehawken  Side,  P.  R.R 58-62 

P.  R.R.  Terminal  Station 92 

Air  Power  Plant: 

Belmont  Tunnels 148-152 

Bergen  Hill  Tunnel  53-55 

Cross-Town  Tunnels,  P.  R.R 105-106 

East  River  Tunnels,  P.  R.R 114-121 

Hudson-Manhattan  Tunnels 166-167 

North  River  Tunnels,  :Manhattan  Side,  P.  R.R 58-62 

North  River  Tunnels,  Weehawken  Side,  P.  R.R 58-62 

P.  R.R.  Terminal  Station 92 

Air  Cylinder  Lubrication 249-250 

Air-Lift  Data 251-255 

Altitude  Compression 246-249 

Beach  Pneumatic  Railway 5 

Belmont  Tunnels 148-153 

"             "       Air-Power  Plant 148-152 

Bends 13 

Bergen  Hill  Tunnel,  P.  R.R.: 

Compressed  Air  Requirements 54-55 

Contractor's  Plant 53-55 

Developments 39 

Drilling  Cost 48-49 

Drill  Steel  Used 47-48 

Explosives 48 

Quantities  of  ^Materials  Used 56 

Simplon  Tunnel  Compared 49 

367 


368  INDEX 


Bergen  Hill  Tunnel,  P.R.R. — Continued. 

Typical  Cross-section 47 

Ventilation 51 

Blasting  Gelatine 312 

Blasting,  Cost  of,  North  River  Tunnels 78-80 

Blasting  in  Open  Cuts,  Cost  of 312-318 

' '       ,  Tunnel,  Explosives  for 307-310 

Brickwork,  Cost  of,  iti  New  York  Subway 36 

Bridge  Caissons 334-338 

Broadway  Underground  Railway 5 

Brooklyn-Manhattan  Division,  New  York  Subway: 

Cost 27 

East  River  Tunnels 30 

Methods  of  Excavation 28 

Route 27 

Structural  Designs 27 

Cameron  Pump  and  IngersoU  Drill 278-280 

Caissons,  Bridge 334-338 

Caisson  Disease 207-209 

Caissons,  Pneumatic 322-334 

334-338 

Classification  of  Compressor  Tj-pes 213-214 

Comparison  of  Costs — Steam  and  Compressed  Air 33 

Compound  Air  Compression 237-246 

Compressed  Air  in  Subway  Construction 32 

Compressed-Air  Locomotives 256-261 

Compressed-Air  Plenum 205-209 

Compressed-Air  Requirements,  Bergen  Hill  Tunnel,  P.  R.R 54-55 

Concrete,  Cost  of,  in  New  York  Subway 36 

Concrete  Cost,  North  River  Tunnels,  P.  R.R 85-87 

Contractors'  Plant,  Bergen  Hill  Tunnel,  P.  R.R 53-55 

Contractors'  Equipment,  Cross-Town  Tunnels,  P.  R.R 105-106 

Contractors'  Plant,  P.  R.R.  Terminal  Station 93 

Cost  of  Brickwork,  New  York  Subway 36 

Blasting  in  Open  Cut 312-318 

North  River  Tunnels,  P.  R.R 78-80 

Concrete — North  River  Tunnels,  P.  R.R 85-87 

' '         in  New  York  Subway 36 

Crushed  Stone— North  River  Tunnels,  P.  R.R 63 

Drilling— Bergen  Hill  Tunnels,  P.  R.R 48-49 

' '      — Electric-Air  Drill 292-294 

' '      —North  River  Tunnels,  P.  R.R 70-71-79-80-81 

Drill  Sharpening 304 

Earthwork  in  New  York  Subway 36 

Excavation — North  River  Tunnels,  P.  R.R 80 

Cost,  Estimated,  P.  R.R.  Developments 39 


INDKX  :i09 


Cost  of  Labor — Xurlh  River  Tunnels,  P.  R.R. .  .   69-70,  71-72,  74,  79,  81,  84,  86,  87 

"'       Mucking — North  River  Tunnels,  P.  R.R 70,  72,  74,  79,  81,  84, 

' '       Open  Cut  Excavation  in  New  York  Subway 34 

"       Operating  Power  Plant — North  River  Tunnels,  P.  R.R (51-62 

"       Timbering — North  River  Tunnels,  P.  R.R 72-74 

"       Shaft  Sinking — East  River  Tunnels,  P.  R.R  ...                       i.H-i.S5 

Cross-Town  Tunnels,  P.  R.R.: 

Air-Power  Plant .  105-10O 

Contractors'  Equipment 105-106 

Disposal  of  Material 106 

Methods  of  Excavation .  107-1 10 

Crushed  Stone,  Cost  of.  North  River  Tunnels,  P.  R.R..                       63 

Dampness  and  Dynamite 311 

Drilling  Cost,  Bergen  Hill  Tunnel,  P.  R.R 48-49 

Drilling  and  Blasting,  Cost  of.  North  River  Tunnels,  P.  R.R 78-80 

Drilling  Cost,  North  River  Tunnels.  P.  R.R 70.  71 .  79.  80,  81 

Drill  Steel,  Bergen  Hill  Tunnel,  P.  R.R 47-48 

Dynamite,  Dampness  and 311 

Earthwork,  Cost  of,  New  York  Subway 36 

East  River  Gas  Tunnel 10 

East  River  Tunnels,  P.  R.R 111-147 

Air  Consumption 143-145 

Air-Power  Plant 114-121 

Air  Pressures  Carried 132 

Clay  Blanket 145 

Cost  of  Shaft  Sinking 134-135 

Costs  of  Various  Operations 14/ 

Developments 41-42 

Materials  and  Formation  Penetrated 126-127 

Methods  of  Excavation 135-142 

Methods  of  Lining 145 

Shaft  Sinking 133-135 

Shield  Construction  and  Operation 123-132 

Specifications  of  Contract 1 1  i-i  14 

Working  Gangs  in  Air  Pressure 13- 

Electric-Air  Drill -'83-292 

Cost  of  Drilling 292--'94 

Electric  Driven  Compressors -17 

Elevated  Railways,  Original 4-6 

Engineering  Data 34^^365 

Excavation,  Cost  of.  North  River  Tunnels,  P.  R.R 80 

"            Methods  of,  P.  R.R.  Terminal  Station 06-9S,  100-103 

Explosives,  Bergen  Hill  Tunnel,  P.  R.R 48 

"         ,  North  River  Tunnels,  P.  R.R 7o 

"          for  Tunnel  Blasting ■'■ 307-310 

"          Terminal  Station,  P.  R.R 103 


370  rXDKX 

PAGES 

Foundation  Problems  in  New  York  City 322-334 

{>et)logical  Formation  of  Manhattan  Island 1-6 

Clray  Canon  Quarry ^^ 

Hammer  Drills 270 

Harlem  River  Tunnel,  New  York  Subway 23 

Historical  Data  on  New  York  Rapid  Transit 1-6 

Hudson  Manhattan  Tunnels 155-167 

Air- Power  Plant 166-167 

Caisson  Construction 163-165 

Method  of  Lining 160 

Hudson  Terminal  Station 168-181 

Caisson  Construction 174-176 

Method  of  Construction 1 74-1 76 

Quantities  of  Materials 1 76 

Traffic  Arrangements i6q-i  73 

Hudson  Tunnel,  Original 7 

Hydraulic  Air  Compressor 219-225 

Ingersoll  Drill  and  Cameron  Pump 278-280 

Labor  Costs — North  River  Tunnels,  P.  R.R.  .  .    60,  70,  71,  72,  74,  70,  81,  84,  86,  87 

Manhattan-Bronx  Division,  New  York  Subway 16 

Amount  and  Character  of  Excavation 2b 

Blasting  and  Drilling 21 

Division  by  Sections,  Prices 16 

Harlem  River  Tunnel 23 

Length 26 

Quantities  of  Materials 26 

Structural  Design 18 

Meadows  Division,  P.  R.R.,  Developments 39 

Methods  of  Excavation,  Cross-Town  Tunnels,  P.  R.R 107-110 

"               "            East  River  Tunnels,  P.  R.R 135-142 

Mucking  Cost,  North  River  Tunnels,  P.  R.R 70,  72,   74,  79,  81,  84 

New  York  Subway 16-36 

Cost  of  Brickwork 36 

Cost  of  Concrete 36 

Cost  of  Earthwork 36 

Cost  of  Excavation  in  Open  Cut 34 

Wages  Paid  in  Construction 35 

North  River  Bridge  Co 37 

North  River  Tunnels,  P.R.R.: 

Analysis  of  Drilling  Operations 78-80 

Developments 39 

Bulkheads ' 70-71 

Concrete  Cost 85-87 


INDKX  371 


North  River  Tunnels,  P.  R.R.:  — Continued. 

Cost  of  Crushed  Stone 63 

Cost  of  Drilling 70,  7 1 ,  79,  80,  81 

Cost  of  Drilling  and  Blasting 78-80 

Cost  of  Driving  Shields 70,  72,  74,  84 

Cost  of  Erecting  Lining 70,  72,  74,  84 

Cost  of  Excavation 80 

Cost  of  Mucking 70,  72,  74,  79,  81,  84 

Cost  of  Power  Plant  Ojjcralion 61-62 

Cost  of  Tunneling 72,  74 

Crushed  Stone  Plant 63 

Explosives 77 

Manhattan  Power  Plant 62-68 

Manhattan  Shaft 57 

Quantities  of  Materials  Used .'  go 

Shield 64-69 

Typical  Cross-sections 62,  65 

Weehawken  Power  Plant 58-62 

Weehawken  Shaft 57 

Open  Cut,  Cost  of  Blasting  in 312-318 

"         ,  Excavation,  Cost  of,  in  Xcw  ^'()rk  Subwa\' 34 

P.  R,R.  Developments  in  Xew  York  City ,S7~45 

' '        Terminal  Excavation 91-103 

Pit  Sinking  in  Frozen  Quicksand 338-339 

Plug  Drills 270 

Pneumatic  Caissons 322-334,  334-338 

Preface vii-ix 

Prevention  of  Caisson  Disease 207-20Q 

Pumps  for  Sinking  and  Tunneling 319-322 

Quicksand,  Pit  Sinking  in 338-339 

Retaining  Walls,  P.  R.R.  Terminal  Station 94-96 

Rock  Drill  Bits .  295-304 

Rock  Drilling  Methods,  P.  R.R.  Terminal  Station 97-103 

Rock  Drill  ^Mountings 268-270 

Rock  Drills  and  Mountings .  262-270 

Sharpening 305-30*) 

Rules  for  Working  in  Compressed  Air 12 

Shield  Construction  and  Operation,  East  River  Tunnels,  P.  R.R 123-132 

Simplon  Tunnel,  Comparison  of,  with  Bergen  Hill  Tunnels 40 

Special  Txpes  of  Air  Compressors 21 7-225 

Steam,  Useful  Information  on 350-351 

Straight  Line  and  I)ui)le\  Comjiressors 226-236 


372  INDEX 

PAOES 

Tables: 

Air  Required  by  Rock  Drills 340 

Areas  of  Circles 354 

Capacity  of  Pumps 357 

Coal  Consumption  of  Engines 364 

Compressed  Air  for  Pumping  Plants 349 

Compressor  Capacitj*  for  Rock  Drills 341 

Contents  of  Cylinders 358 

Density  of  Gases  and  \'apors 348 

Eeed  Water  Consumption  of  Engines 365 

Flow  of  Air  through  an  Orifice 348 

Friction  Losses  in  Fire  Hose 363 

Friction  Losses  in  Water  Pipes 361-362 

Heat  of  Combustion  in  Fuels 365 

Heights  for  Pumping  Water 359 

Horse-power  Required  to  Compress  Air 346 

Loss  of  Air  Pressure  in  Valves,  Tees,  and  Elbows 346 

Loss  of  Air  Pressure  in  Transmission 342-345 

Loss  of  Work  Due  to  Heat  in  Air  Consumption 347 

Metric  Measures 364 

Pressure  of  Water 353 

Ratio  of  Cylinder  Areas 355-356 

Standard  Pipe  Dimensions 360 

Water  Jets 363 

Terminal  Station,  P.  R.R. 

Air-Power  Plant 92 

Contractor's  Equipment 93 

Developments 39~4i 

Disposal  of  Materials 98-102 

Explosives 103 

Methods  of  Excavation 96-98,  100-103 

Quantity  of  Materials 98-103 

Retaining  Walls 94-96 

Rock  Drilling  Methods 97-103 

Topography  of  Manhattan  Island 1-6 

Train  Movement,  P.  R.R.  Terminal 45 

Tribute v-vi 

Tunnel  Carriage  for  DriUing 281-283 

Timbering  Cost — North  River  Tunnels,  P.  R.R 72-74 

Tunnsl  Shield— North  River  Tunnels,   P.  R.R 64-69 

Use  of  Compressed  Air  in  Tunneling 210-216 

Ventilation  in  Bergen  Hill  Tunnels 51 

Water  Impulse  Compressors 217 

"     ,  Useful  Information  on 35i~352 

Wages  in  New  York  Subway  Construction 35 


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Water  and  Public  Health 12mo, 

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8vo, 

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Water-supply.      (Considered  principally  from  a  Sanitary  Standpoint). 

8vo, 

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1 

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*  Merriman's  Elements  of  Sanitary  Engineering 8vo, 

Ogden's  Sewer  Construction 8vo, 

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Venable's  Garbage  Crematories  in  America 8vo. 

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/i6e 


/=>er'Ar:jD9t. 


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JAN  2  0  REC'D 


fcnginecnn'. 
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